Lens shutter camera including zoom lens

ABSTRACT

A lens shutter type of camera is disclosed in which a zoom lens is positioned in a lens block (1) which has a sector gear (15) rotatably associated with the lens block and with a rotatable cam ring (14). The cam ring and sector gear are rotatable in a substantially constant axial position. A movable finder optical assembly (8) and a movable strobe assembly (9) are movable in association with movement of the zoom lens. The zoom lens is movable between an extreme telephoto position and an extreme wide angle position, as well a into a fully collapsed lens position beyond the extreme wide angle position and a macro or close-up photographing position beyond the extreme telephoto position. When the camera is in its macro mode, a prism (P1) is inserted into the finder optical assembly to correct for parallax; the strobe assembly is moved to change its illumination angle; and an optical wedge (4e) is pivoted into the path between a light receiver (4) and a light emitter (3e). A single cam plate (53) is provided to move the finder assembly and the strobe assembly. The photographic aperture (22b) can be selectively closed by barrier plates (31a) when the zoom lens is moved into its fully collapsed position. A light intercepting assembly (210) is provided for preventing light from entering the photographic optical assembly via cam grooves (20 and 21). This intercepting assembly includes a flexible code plate (90) which surrounds a peripheral portion of the cam ring (14) and which provides positional information relating to the position of the zoom lens.

This application is a continuation of application Ser. No. 08/462,687,filed Jun. 5, 1995, which is a continuation of application Ser. No.08/222,697, filed Mar. 10, 1994 now U.S. Pat. No. 5,465,131, which is adivision of application Ser. No. 07/924,631, filed Aug. 4, 1992, nowU.S. Pat. No. 5,321,462, which is a continuation of application Ser. No.07/480,214, filed Feb. 14, 1990, now U.S. Pat. No. 5,157,429, which is adivision of application Ser. No. 07/144,030, filed Jan. 7, 1988, nowU.S. Pat. No. 4,944,030.

BACKGROUND OF THE DISCLOSURE

1. Technical Field

The present invention generally relates to a lens shutter type ofauto-focus camera, and more particularly to a zoom lens type of camerain which a zoom lens system is used as a taking or photographing opticalsystem, and in which a finder optical system and an electronic flashdevice (i.e., a strobe) are associated with the zooming operation of thezoom lens system. In other words, the finder optical system and thestrobe move in coordinated fashion with zooming movement of the lens.

This application is related to the commonly assigned application filedon even date herewith, application Ser. No. 143,946, entitled "Zoom LensDrive System for lens shutter type of Camera", now U.S. Pat. No.4,936,664 the disclosure of which is expressly incorporated by referenceherein.

2. Background Art

Generally, in conventional lens shutter (i.e., between the lens shutter)types of auto focus cameras, it is impossible to vary the focal lengthof the photographic optical system. Other lens shutter types of autofocus cameras comprise a two focal length system, in which a lens isprovided for varying the focal length and can be selectively inserted inthe photographing optical system. In such a system, two focal lengthsare provided; however, it is possible to use only the two focal lengthprovided, e.g., a wide angle and a telephoto range for the zoom lens,or, e.g., a standard range and a telephoto range for the zoom lens.While taking advantage of such dual focal lengths, it is impossible tocover the range of focal lengths between the two extreme focal lengths,or between a wide angle and a medium telephoto focal length. Under suchcircumstances, taking pictures with the use of a zoom lens hasheretofore only been possible by using a single lens reflex camera.

However, single lens reflex cameras are more expensive and heavier thanlens shutter type cameras, and, accordingly, it is not easy for aphotographer who is unfamiliar with cameras to freely use such singlelens reflex cameras. Because of the heavy weight and relatively largesize of such single lens reflex cameras, female photographers andtravelers who are desirous of reducing the weight and the amount ofbaggage carried tend to hesitate to use such a single lens reflex(hereinafter SLR) camera, even if they appreciate the high qualitypictures which are generally taken by such cameras.

Accordingly, users who would otherwise hesitate to use single lensreflex cameras which are relatively bulky and heavy, as noted above,have only two alternate choices: (a) a relatively small, light lensshutter type of automatic camera which has heretofore not been capableof controlling the focal length of the photographing optical system; or(b) a dual focal length type of auto focus camera in which only twoextreme focal lengths can be used.

In view of such circumstances, one primary object of the presentinvention is to provide a small, light, compact lens shutter type ofcamera with a zoom lens in which focusing control and electronic flashor strobe control can be automatically effected.

Another object of the present invention is to provide a lens shuttertype of auto-focus camera which has an additional macro (i.e., close-up)function with which an extremely large, detailed image can be taken; andin which a finder optical system and an electronic flash device areadapted to be coordinated with zooming operation of the zoom lens in themacro mode as well as in normal operation (e.g., in wide angle,telephoto or standard operation).

Yet another object of the present invention is to provide a movablemacro compensating optical element which is used in the distancemeasuring apparatus or range finder in order to extend the optical baselength from its value in the normal photographic mode, and to enablesubstantially the same area on the position detecting sensor to receivelight when measuring the distance of a subject.

Still another object of the present invention is to provide a camerahaving a field of view with minimum parallax in the macro mode.

Another object of the present invention is to reduce parallax in a lensshutter type camera by providing a prism selectively movable into thepath of a finder optical system in order to deflect the field of viewdownwardly and rightwardly to the axis of the photographing opticalsystem when the camera is in its macro photographing mode.

Still a further object of the present invention is to move a strobe lampassembly along an optical axis thereof in coordination with movement ofa zoom lens.

Yet another object of the present invention is to provide a distancemeasuring device used in an auto-focus lens shutter type of camera inwhich an optical wedge is selectively inserted to extend the opticalbase length between the light emitter and the light receiver comprisingthe distance measuring device.

Still another object is to provide a finder optical system in which itis necessary to move only a single lens to vary the field of view.

Another object is to provide a lens shutter type camera with a lightintercepting assembly which minimizes light from entering a photographicoptical assembly lens system.

Still a further object of the present invention is to provide a lensshutter type of camera which includes a strobe assembly whoseillumination angle varies in accordance with the position of a movablezoom lens assembly.

Yet another object of the present invention is to provide a lens shuttertype camera in which a flexible printed circuit board is guided in itsmovement along one side of a cam ring and zoom lens, and which includesstrucure for minimizing internal reflections from the FPC board into theinterior of a photographing optical assembly.

DISCLOSURE OF INVENTION

The present invention provides a lens shutter type of camera having asubject distance measuring device, a photographing optical system whichis driven in response to measurement of the subject distance which isdetected by the subject distance measuring device, a finder opticalsystem which is independent of the photographing optical system, and astrobe. In accordance with the present invention, the photographingoptical system comprises a zoom lens assembly which is capable ofsuccessively varying the focal length of this optical system; the finderoptical system is independent of the photographing optical system andcomprises a variable power finder optical lens assembly which is capableof varying the field of view of the finder lens assembly, in accordancewith the specific focal length of the zooming lens system at any pointin time; and the zoom lens system and the variable power finder opticalsystem are driven by a single zooming motor.

With such an arrangement, only the zooming operation and the shutterrelease operation will be manually effected, resulting in a highquality, compact automatic camera.

The lens shutter type of camera used in the present invention isfunctionally equivalent, or in fact superior, to a single lens reflexcamera, insofar as it incorporates a strobe device, thereby providing ahighly systemitized, auto-focus camera which is easy to use and handle.

The strobe device can be of a type, e.g., in which the illuminationangle will be fixed, but is preferably a variable illumination anglestrobe device which is capable of varying the illumination angle inaccordance with, or in response to, the variable focal length of thezoom lens system.

In accordance with the present invention, the zoom lens system caneither be partially or completely moved in the direction of the opticalaxis of the photographing optical system, beyond one of the focal lengthextremities, when the camera is placed into the macro mode. Anotherfeature of the present invention is that the finder optical systemcomprises a variable power finder optical system which includes anoptical element which is capable of varying the field of view, theoptical element varying the field of view in accordance with or inresponse to the particular focal length of the zoom lens system. Thefinder system includes an optical element which is capable of deflectingthe finder optical axis towards the optical axis of the photographingoptical system in order to correct parallax in the macro mode of thecamera.

In accordance with yet another feature of the present invention, astrobe device comprises a variable illumination angle strobe devicewhich is capable of varying the strobe illumination angle in accordancewith the focal length of the zoom lens system and in association with orin response to movement or transfer of the zoom lens (photographinglens) system into the macro mode.

The subject distance measuring device of the present invention iscapable of detecting the subject distance by a conventionaltriangulation measuring method, which has been adopted to ensure precisedetection of the subject distance, even when the camera is in its macromode; this distance measuring device includes an optical element whichis capable of deflecting the distance measuring light in order tooptically extend the base length of the measuring device in response totransfer or movement of the zoom lens system into the macro mode.

In one aspect of the present invention a lens shutter type of auto focuscamera is provided which has a zoom lens which is continuously movablebetween an extreme wide angle position and an extreme telephotoposition. The lens is movable beyond the extreme telephoto position intoa macro or close-up photographing position; and it is movable beyond theextreme wide angle position into a closed position in which thephotographing lens is completely collapsed and in which lens barriersare provided to close an opening in a lens barrier block. The finderfield of view and strobe illumination angle in the camera vary inaccordance with the zooming operation of the lens, as well as when thepicture of a subject is taken in a macro mode at a close distance.Focusing can be automatically controlled in both the macro mode and inany range of the zooming lens. An optical wedge is adapted to bepositioned along the optical path of the distance measuring device whichforms a portion of the automatic focusing system of the camera. A prismis adapted to be pivoted into the optical path of the finder opticalsystem in order to correct for parallax in the macro mode. A cam plateis provided which is driven by a single motor, which also drives thezoom lens via a cam ring; and the cam plate is adapted to drive thefinder optical system and the strobe light assembly in accordance withzooming operation of the zoom lens.

In a second aspect, the present invention provides a lens shutter typeof camera having a zoom lens driven by a motor. The camera furthercomprises a finder optical assembly and means for moving the finder inaccordance with zooming movement of the lens in order to vary the fieldof view through the finder.

In a third aspect, the present invention provides a lens shutter type ofcamera having a zoom lens driven by a motor, a movable strobe lightassembly with a variable illumination angle, and means for moving thestrobe assembly in accordance with zooming movement of the zoom lens.

In a fourth aspect of the present invention, a lens shutter type ofcamera is provided having a zoom lens driven by a motor, means fordriving the zoom lens continuously between an extreme wide angleposition and an extreme telephoto position, as well as means for drivingthe zoom lens beyond the telephoto terminal position in order to take aclose-up or macro photograph.

The camera includes an automatic focusing mechanism which comprises asubject distance measuring device which measures the distance of thesubject from the film plane of the camera by triangulation.

The distance measuring device includes an optical wedge which is movableinto the path between a light emitter and a light receiver in order toextend the base length of the subject distance measuring device when thecamera is placed into the close-up photographic mode.

A rotatable cam ring is attached to the zoom lens which houses thephotographic optical assembly, and a rotatable gear is positioned aboutthe cam ring. The cam ring includes a recess and an adjacent projectionwhich are adapted to engage a lower end of the optical element and topivot the optical element in front of the light receiver of the distancemeasurement device, and against the biasing force of a spring attachedto the optical element.

The finder optical assembly and the strobe assembly can be positionedinto a plurality of positions in response to or coordination withcontinuous movement of the lens over an infinite number of positions.This is achieved by the use of a code plate which defines thirteenpositions, including extreme telephoto and extreme wide angle positions.

In a fifth aspect, the present invention discloses an automatic focuscamera with a lens movable into a macro photographic position. Thiscamera includes a subject distance measuring device which comprisesmeans for determining the distance of a subject from a film plane in thecamera. The camera further includes a photographic optical system whichis automatically focused in accordance with the detected distance of thesubject. The optical system is movable to an extreme telephoto positionand to a macro or close-up position beyond the extreme telephotoposition. The subject distance measuring device comprises an opticalelement and means for selectively inserting the optical element into theoptical path of the subject distance measuring device. The opticalelement is positioned within a frame or mask which is attached to aflexible correction flag; the flag is pivotably connected to a camerabase at one end, and has a second, free end to which the compensatingoptical element is positioned. A cam ring includes a rotatable gearthereon and includes a recess and an adjacent projection which areadapted to pivot the flag to overcome the bias of a spring whichcontinuously biases the correcting flag into a retracted position awayfrom from the optical path of the light receiving element of thedistance measuring device.

In another aspect, the present invention provides a zoom lens adapted tobe positioned in a camera. The lens includes at least a first lens groupand a second lens group and means for positioning the photographingoptical system of the zoom lens in an extreme wide angle position and anextreme telephoto position. The zoom lens further comprises means formoving only the first lens group into a position beyond the extremetelephoto position in order to provide close-up focusing of thephotographic optical system when the camera is in a macro photographingmode.

In a further aspect of the present invention, a camera is providedhaving a zooming lens positionable in an extreme wide angle position, anextreme telephoto position, and a plurality of variable magnificationpositions located between these two extreme positions, as well as in aclose-up position beyond the extreme telephoto position. The cameraincludes an auto focus assembly comprising a light emitter and a lightreceiver, the light receiver comprising a position sensing device whichhas a first area which is used to sense the position of a subject duringautomatic focusing for all lens positions except a macro position, and asecond area closely adjacent to the first area and which comprises meansfor sensing the position of a subject during macro focusing of thecamera. These two areas can either be identical or overlapping.

The camera can comprises a zoom lens movable between an extreme wideangle position and an extreme telephoto position, and a plurality ofvariable magnification positions between the two extreme positions, aswell as into a focusing position which is located beyond the extremetelephoto position. The camera includes a device for measuring thedistance of a subject from the film plane of the camera whichincorporates a light receiver and a light emitter. An optical element isselectively positionable in the optical path between the light receiverand the light emitter, and a motor is provided for driving the lens.Means are provided for drivably connecting the motor to the lens, andfor positioning the optical element between the light emitter and thelight receiver when the lens is moved into the close-up or macrofocusing position.

The lens shutter type camera includes a photographic optical systemhaving a zooming function and a macro function, and includes anindependent finder optical system which comprises a first lens grouphaving a negative refractive index and which comprises a positive lensand a negative lens, a second lens group comprising a negative lens, athird lens group having a positive refractive index, and a prism whichis adapted to be selectively inserted into the optical path between thetwo lenses of the first lens group. The prism comprises means fordeflecting the optical path of the finder optical system towards theoptical axis of the photographic optical system when the prism ispositioned between the lenses of the first group.

In still another aspect of the present invention, a finder opticalsystem is provided in a lens shutter type of camera which has aphotographing optical system which can have a macro photographingposition. The finder optical system is independent of the photographingoptical system and comprises at least one lens and an optical elementwhich is selectively inserted into the finder optical system when thephotographic optical system, i.e., the zoom lens, is in the macro mode.The optical element comprises means for correcting parallax bydeflecting the optical axis of the finder optical system towards theoptical axis of the photographic optical system.

A movable cam plate can be provided for the camera, and will be adaptedto be driven by a motor. The cam plate comprises a substantially flatmain portion, a downwardly extending rack attached to a rear end of themain portion, and a plurality of grooves located in the main portion.The grooves include a parallax compensating cam groove having anon-projecting section, a forward macro feeding section, and a macrofixing section; a strobe assembly guide groove having a wide anglesection, a variable power section, and a telephoto section; and avariable lens guide groove having a wide angle section, a telephotosection, and a variable power magnification section.

In still another aspect, the lens shutter type camera comprises aphotographing optical system including a zoom lens with a movablevariable power lens group for varying the focal length of this opticalsystem. An independent finder optical system is provided which has avariable power lens group for varying the finder field of view inaccordance with the varying focal length of the zoom lens system, and avariable illumination angle strobe assembly is provided with a lampwhich is movable in accordance with the focal length of the zoom lenssystem. A motor is provided for moving the zoom lens system variablepower lens group, and a single cam plate is adapted to move inassociation with movement of the zoom lens. Movement of the cam platemoves the finder optical system via a first driven pin which is engagedin one groove in the cam plate, and the strobe assembly is moved via apin which is attached to the strobe assembly and which is engaged in asecond groove in the cam plate.

A lens cap opening mechanism is provided which is adapted to be usedwith a lens support frame having an outer periphery, a central opening,and at least one barrier plate for selectively closing the opening. Themechanism comprises a movable member positioned in a peripheral openingof the frame, with the member being engaged with the at least onebarrier plate. Means are provided for selectively moving the memberinwardly of the frame to close the opening with the at least one barrierplate.

The camera includes a zoom lens which can be moved by a driving motorinto a collapsed lens position rearwardly of an extreme wide angle lensposition. The lens is supported by an exterior frame having a centralphotographic opening and one or more barriers are provided forselectively closing the central opening. The camera comprises means formoving the barriers to close the opening when the lens is moved into thecollapsed lens position and for opening the barriers in all other lenspositions.

A light blocking mechanism is used in the lens shutter type camera whichhas a cam ring with at least one camming groove therein. The cam ring isrotatable in a constant axial position, and the light blocking mechanismcomprises at least one light intercepting member positioned about theperiphery of the cam ring. The light intercepting member comprises meansfor covering each of the cam ring grooves and for thereby preventinglight from entering the interior of the cam ring.

In a lens shutter type of camera having a cam ring rotatable in aconstant axial position and at least one movable lens barrel movablealong an optical axis of a photographing optical system in response torotation of the cam ring, a light interception member is provided whichis positioned in a space between a front end of a cam ring supportmember and a front cover having an opening through which the lens barrelis adapted to move.

A flexible printed circuit board, i.e., an (FPC), is provided in thelens shutter type of camera and is adapted to conduct operationalsignals from the camera body to a shutter block attached to an axiallymovable lens barrel within the camera. A guide plate is provided for theFPC which has a front end with at least one bent portion and a rear endattached to the camera body which has a second bent guide portionthereon. The front guide plate end is attached to the shutter block. Thelens shutter type of camera can also include an anti-reflection deviceattached to the flexible printed circuit board.

In another aspect of the present invention, a lens shutter type ofcamera is provided having a photographing optical system with a zoomlens having a rotatable cam ring with cam grooves engaged by at leastone lens group in the zoom lens which is movable along an axis of thephotographing optical system in order to vary the optical length of thisoptical system in response to rotational motion of the cam ring. The camring includes at least one flexible code plate attached to the ringwhich includes zoom lens positional information thereon.

Other objects, features and advantages of the present invention willhereinafter be described.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features, and advantages of the presentinvention will be described in greater detail with respect to theaccompanying drawings, in which like reference numerals representsimilar elements throughout the several views, and wherein:

FIG. 1 is a schematic perspective view of a first embodiment of a lensshutter type of camera having a zoom lens formed in accordance with thepresent invention;

FIG. 2 is a front elevational view of a lens barrel block, a lightemitter, a light receiver, and a macro-compensating optical elementwhich forms a part of a distance measuring device, together with azooming motor, all forming a portion of the invention of FIG. 1;

FIG. 3 is a top plan view of the apparatus of FIG. 2;

FIG. 4 is a sectional view taken along line IV--IV of FIG. 2;

FIG. 5 is a sectional view of the apparatus of FIG. 2 taken along lineV--V of FIG. 2;

FIG. 6 is a longitudinal sectional view of a lens barrel block and twophotographing optical lenses formed in accordance with the presentinvention;

FIG. 7 is a developed view of the camming grooves in a "flattened" camring used to surround the front and rear lens element groups of thephotographic optical system of the camera of FIG. 1;

FIG. 8 is an exploded perspective view of a lens barrel block used inthe camera of FIG. 1;

FIG. 9 is a sectional view illustrating an optical arrangement foradjusting the focus point of the camera when the camera is placed intoits macro mode;

FIG. 10 is an enlarged plan view of the prism, frame (i.e., mask) andone light receptor lens of the system of FIG. 9;

FIG. 11 is a front elevational view illustrating the assembly of FIG.10;

FIG. 12 is a sectional view of an optical arrangement used in a two lensgroup zooming lens in the camera of FIG. 1;

FIG. 13 is a schematic view illustrating the light emitter and lightreceptor of a distance measuring device used in the camera of FIG. 1;

FIG. 14 is a sectional view of an optical arrangement of a system foradjusting the focal point of the object distance measuring system whenthe camera is in a macro mode;

FIGS. 15A-17A are vertical sectional views of a first embodiment of afinder optical system used in accordance with the present invention, inwhich:

FIG. 15A is a side plan view of the finder optical assembly when in awide field, small magnification position;

FIG. 16A is a plan view of the assembly of FIG. 15A when the camera isin a narrow field, large magnification mode;

FIG. 17A is a plan view of the assembly of FIG. 15A when the camera isin a narrow field, large magnification position when the camera is inits macro mode;

FIGS. 15B-D, 16B-D and 17B and C respectively, illustrate theaberrations of the optical systems of FIGS. 15A, 16A and 17A,respectively.

FIGS. 18B-D, 19B-D and 20B and C are all vertical sectional views of asecond embodiment of a finder optical system formed in accordance withthe present invention in which:

FIG. 18A is a plan view of the optical system when the camera is in awide field, small magnification mode;

FIG. 19A is a plan view of the optical system when the camera is in anarrow field, large magnification mode; and

FIG. 20A is a plan view of the optical system when the camera is in anarrow field, large magnification macro mode;

FIG. 21 is a plan view of a cam plate which can be attached to a portionof the finder block and the strobe lamp assembly of the presentinvention;

FIG. 22 is a sectional view taken along line XXII--XXII of FIG. 21;

FIG. 23 is a back plan view of the cam plate of FIG. 21;

FIG. 24 is a plan view of the apparatus of FIG. 21 with the cam plateremoved;

FIG. 25 is a sectional view taken along line XXV--XXV of FIG. 21;

FIG. 26 is a sectional view taken along line XXVI--XXVI of FIG. 25showing the finder plate in a first position;

FIG. 27 is a sectional view similar to that of FIG. 26 but illustratingthe finder plate in a second, operational position;

FIG. 28 is a sectional view similar to the view of FIG. 26, in which adeflecting prism actuating plate has been removed to facilitateconsideration;

FIG. 29 is a front elevational view of the apparatus of FIG. 25, shownin a position in which a deflection prism actuating plate is inserted;

FIG. 30 is a sectional view taken along line XXX--XXX of FIG. 29;

FIGS. 31 and 32 are sectional views of a first embodiment of an opticalbarrier mechanism, as viewed along a plane which is perpendicular to anoptical axis, when in its open position with the central lens frameopening being open;

FIG. 32 is a sectional view similar to that of FIG. 31 but illustratingthe optical barrier mechanism when it is in its closed position;

FIG. 33 is a sectional view of a second embodiment of an optical barriermechanism formed in accordance with the present invention, the viewbeing similar to that of the first embodiment of the optical barriermechanism illustrated in FIG. 31;

FIG. 34 is a sectional view of the optical barrier mechanism of FIG. 33in its closed position, similar to the view of the embodiment of FIG.32;

FIG. 35 is an exploded perspective view of a light interceptingmechanism positioned adjacent to a lens barrel block;

FIG. 36 is a perspective view of a light intercepting ring;

FIG. 37 is a sectional view taken along line XXXVII--XXXVII of FIG. 36;

FIG. 38 is a sectional view of a second embodiment of a lightintercepting ring formed in accordance with the present invention whichis similar to the view of FIG. 37;

FIG. 39 is an exploded perspective view of one embodiment of a guidingdevice for a flexible printed circuit board (i.e., an FPC) with the camring being partially cut away;

FIG. 40 is a perspective view of the FPC board guide member of FIG. 39;

FIG. 41 is a sectional view of a mechanical arrangement of an FPC boardguide plate with respect to the space defined between the cam ring and afront lens group frame;

FIG. 42 is a side elevational view of an FPC board which is illustratedin extension (in dashed lines) and in a deformed position (in solidlines), respectively;

FIG. 43 is a side elevational view of a light intercepting means used inassociation with an FPC board;

FIG. 44 is a developed or schematic view of a code plate, with the lensof the code plate and grooves of the cam being illustrated on aflattened cam ring, illustrating the functional relationship betweenconductive lands on the code plate and the cam (ring and plate) grooves;

FIG. 45 is a table illustrating the zoom code on the code plate of FIG.44 and the stopping positions which are located on the code plate;

FIG. 46 is a front elevational view of the operational switches of acamera formed in accordance with the present invention;

FIG. 47 is a back elevational view of the camera of the presentinvention illustrating a zooming lens operation switch thereon;

FIG. 48 is a top plan view of the camera of FIGS. 46 and 47,illustrating additional operational switches;

FIG. 49 is a schematic sectional view illustrating a mode changingswitch formed in accordance with the present invention in a first,inoperative position;

FIG. 50 is a sectional view of a mode changing switch and a macro buttonillustrated in a second operational position;

FIG. 51 is a schematic view of an alternative telephoto-wide angleswitch of the camera of the present invention;

FIG. 52 is a front plan view of a finder optical system lens having aplurality of bright frames thereon;

FIG. 53A is a perspective view of a double-wedge shaped prism used inthe present finder optical system;

FIG. 53B is a top plan view of the prism of FIG. 53A; and

FIG. 53C is a right hand side plan view of the prism of FIG. 53A.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described below in greater detail,with specific reference to the accompanying drawings which illustrate avariety of embodiments and features of the present invention.

The description will be generally provided in accordance with thefollowing general sub headings:

A. The Overall Camera Construction for a Lens Shutter Type of Camera

B. Distance Measuring Device, i.e., Range Finder, and Camera MacroFunctioning Thereof

C. Finder Optical System

D. Finder and Strobe Driving Mechanisms

E. Barrier, i.e., Lens Cap, Mechanism

F. Light Interception Assembly and Mechanism

G. FPC Board Guide and Anti-Reflection Mechanism

H. Mechanism for Detecting Information Relating to the Position of theZoom Lens

A. Overall Camera Construction for a Lens Shutter Type of Camera

The overall construction of a lens shutter type of camera formed inaccordance with the present invention is well illustrated in FIGS. 1-8.A lens shutter type of camera formed in accordance with the presentinvention essentially comprises a zoom lens barrel block 1, a finder andstrobe block 2 (hereinafter referred to as a finder block), a lightemitter 3 and a light receiver 4 forming a portion of a distancemeasuring, i.e., AF, device, and a zooming motor 5 which is used for thezooming operation of the photographing optical system. All of theseelements are secured to a base 6 which forms an immovable portion of thecamera body.

Base 6 includes, as is best illustrated in FIGS. 2-4, a lens barrelsupporting plate portion 6a which lies in a plane which is perpendicularto the optical axis of the lens; and a horizontal supporting plateportion 6b is provided which extends at right angles from the lensbarrel support plate portion 6a. Support plate portion 6b extends beyondthe side edge of plate 6a, as seen in FIG. 2, in order to support finderassembly 8 and strobe assembly 9. The base further comprises motorsupporting plate portions 6c which are positioned perpendicularly withrespect to the horizontal support plate portion 6b. Lens barrel block 1is supported on lens barrel support plate portion 6a, which has acentral opening (unreferenced) for receiving the lens barrel block asillustrated in FIG. 2. A zooming motor 5 is attached to motor supportplate portions 6c and is located above the central portion of lensbarrel block 1. Preferably, only a single such motor (e.g., a DC motor)is used to drivingly engage all of the movable elements of the system. Adistance measuring device includes a light emitter 3 and a lightreceiver 4, which are secured to the horizontal support plate portion 6bof base 6, and which are located on opposite sides of zooming motor 5(see FIGS. 2 and 3). Finder block 2 is secured to the right hand portionof horizontal support plate portion 6b, as viewed from the front of thecamera as seen in FIG. 2. A gear train support plate portion 6e isconnected to motor support plate portion 6c via spacer 6f, as bestillustrated in FIG. 3.

Lens barrel block 1 is adapted to be actuated by zooming motor 5, andthe construction of this block will be described hereinbelow with morespecific reference to FIGS. 6-10. A rear securing plate 11 is mounted tolens barrel support plate portion 6a of base 6 by fastening screws 10,as is best illustrated in FIG. 6. Rear securing plate 11 includes fourguide rods 12 which are attached to and through bores in the rearportion of the guide plate and which are located about the optical axisof the photographing optical system and parallel to this axis. A frontsecuring plate 13 is secured to the front ends of guide rods L2; theseguide rods and plates are the main securing elements for lens barrelblock 1.

A rotatable cam ring 14 is positioned between front and rear securingplates 13 and 11, respectively; a sector gear 15 is provided about asubstantial portion (but preferably not the entire 360°) of the outerperiphery of cam ring 14; this gear can be attached to the cam ring byconventional means, e.g., via set screws 15a, as seen in FIG. 6; thisgear is adapted to engage, either directly or indirectly, a first pinion7 (FIG. 1) which is positioned between the gear train support plate 6eand the motor support plate portion 6c, as seen in FIGS. 3 and(particularly) FIG. 5. Gear 15 can be a sector gear which will cover apredetermined range of rotational movement of cam ring 14; a turningrecess 44a and cam surface 44 are provided adjacent to each other on (aflat surface portion of) the gear. The cam ring is itself provided withzooming cam grooves 20 and 21 (see FIG. 7) which are used to engage thefront and rear lens element groups, respectively.

FIG. 7 is a schematic or developed view of zooming cam grooves 20 and 21of ring 14. Cam groove 21, used to engage the rear lens element group,includes an extreme wide angle fixing section 21a, a variablemagnification section 21b inclined upwardly (as seen in FIG. 7) fromsection 21a, and an extreme telephoto fixing section 21c. Cam groove 20,used for the front lens element group, includes a section 20a foropening and closing barrier block 30, a lens retraction section 20b, anextreme wide angle fixing section 20c, a variable magnification section20d, an extreme telephoto fixing section 20e, a macro transfer section20f, and an extreme macro fixing section 20g.

When the term macro is used throughout this specification, it refers toa "close-up" photographing configuration for the camera. Previously, theterm "macro" has occasionally been used to mean "bigger than life";however, the term macro has been used throughout this specification asan equivalent term for close-up, and whenever it is used it should betaken to have such a meaning unless indicated to the contrary herein.

The total angle φ₁ of the rotational displacement of cam ring openingand closing section 20a, lens retraction section 20b, and extreme wideangle fixing section 20c of zooming cam groove 20 is identical to angleφ₁ of the extreme wide angle fixing section 21a of zooming cam groove21. Angle φ₂ of the variable magnification, i.e., variable power,section 20d of zooming cam groove 20 is identical to angle φ₂ of thevariable magnification, i.e., variable power, section 21b of zooming camgroove 21. Further, the total angle φ₃ of the extreme telephoto fixingsection 20e, the macro position fixing section 20g, and the macrotransfer section 20f, is equal to the angle φ₃ of the extreme telephotofixing section 21c. In the illustrated embodiment, the zooming range isbetween approximately 35 mm and approximately 70 mm.

A roller 17, as illustrated in both FIGS. 6 and 8, is positioned withinzooming cam groove 20; this roller is attached to a front lens groupframe 16. A roller 19 of rear lens group frame 18 is positioned withinzooming cam groove 21, again as illustrated in FIGS. 6 and 8. Front lensgroup frame 16 and rear lens group frame 18 are movably guided by guiderods 12, and a decorative frame 22 and shutter block 23 are secured tothe front lens group frame 16 via set screws 22a, as best seen in theexploded view of FIG. 8, as well as in the cross-sectional view of FIG.6.

The front lens frame 24 which supports front lens element group L1 isengaged by shutter block 23 via helicoid 25, which is shown in FIG. 8.Front lens frame 24 includes an arm 24a which engages lens feeding lever23a of shutter block 23 (see FIG. 6), so that when lens feeding lever23a rotates in a circumferential direction in order to rotate front lensframe 24, the front lens frame will move along the direction of theoptical axis of the photographing optical system under the guidance ofhelicoid 25. Rear lens element group L2 is directly attached to rearlens group frame 18, as seen in FIG. 6. One desired configuration oflens groups L1 and L2, as illustrated in FIG. 6, are disclosed incommonly assigned U.S. patent application Ser. No. 935,982, filed onNov. 28, 1986, the disclosure of which is expressly incorporated byreference herein.

The structure of shutter block 23 is known per se. This shutter blockrotates lens feeding lever 23a over a predetermined angular displacementin accordance with a detection signal which is received by the shutterblock from the distance measuring device, as described hereinafter, viaa pulse motor which is incorporated within the camera body and which isadapted to open shutter sector 23b, which has been closed for apredetermined time, and to thereafter return lens feeding lever 23a intoits original position after the shutter has again closed. This type ofshutter block is disclosed, e.g., in unexamined Japanese PublishedPatent Application (KOKAI) No. 60-235,126, dated Nov. 21, 1985, thedisclosure of which is expressly incorporated by reference herein. Thepresent camera utilizes such a shutter block in the fundamental waydisclosed therein.

Finder block 2 includes finder assembly 8 and strobe assembly 9. Thefinder device and the strobe device are adapted to vary, respectively,the field of finder view and the illumination angle, i.e., the intensityof the strobe, in accordance with variance in the focal length of thelens barrel block 1. Zooming motor 5 is used as a power source both forfinder control and strobe control; only a single motor need therefore beused.

As seen in FIG. 1, sector gear 15 of cam ring 14 is engaged by a secondpinion 50 which is different from the first pinion 7 referred topreviously. Shaft 51, to which pinion 50 is attached, extends rearwardlytowards the rear portion of base 6, and is provided with a reductiongear train 52 adjacent a rear end of the shaft. The reduction gear trainincludes a final gear 52a which meshes with a rack 53a of movable camplate 53. This substantially flat cam plate 53 is slidable in right andleft hand lateral directions, as viewed in FIG. 1, and includes adownwardly bent portion 53b at its rear end, as best shown in FIG. 1.Rack 53a is formed on the lower end of bent portion 53b of cam plate 53.Reduction gear train 52 is adapted to reduce rotation of gear 15 inorder to restrict or limit the lateral movement of cam plate 53. The camplate is provided with a variable power cam groove 55 for guidingmovement of finder device 8, a parallax correction cam groove 56, and astrobe cam groove 57 for guiding movement of strobe device 9.

The lens system used in finder optical assembly 8 essentially comprisesa subject lens group L3, an eyepiece group L4, and a movable variablepower lens group L5, and further comprises a deflection prism P1 whichis used when the camera is placed into the macro or close-up mode.

Variable power lens group L5 makes the image picture size, which isadapted to vary in accordance with the variable power operation of lensbarrel block 1, be coincident with the field of view in finder device 8.Deflection prism P1 will enter the optical path of the finder lenssystem only in the macro mode, in order to adjust parallax whichotherwise occurs in such mode. Specifically, parallax which inevitablyoccurs when using lens shutter type of cameras will increase as thesubject whose picture is being taken approaches the camera; and,accordingly, a large parallax would normally result in the macro mode.In order to solve this problem and reduce the large parallax whichotherwise occurs in the macro mode, deflection prism P1 is provided inthe form of a wedge with a thicker lower end and a thinner upper end.Deflection prism P1, when located along the optical axis of the finderoptical system, serves to deflect rays downwardly in order to take apicture of a subject which is located extremely close to the camera.FIG. 28 illustrates the optical path of light rays when the deflectionprism P1 is located along the optical axis of the camera. As describedhereinafter, the wedge prism which is used is preferably selected to bea double wedge prism, which varies in width in both the vertical and inthe horizontal directions, as clearly illustrated in FIGS. 53A, B and C.The use of such a prism bends the light rays downwardly and rightwardly,to move them into substantial alignment with the photographic opticalaxis.

Strobe assembly 9 restricts or limits the illumination angle when thefocal length of the photographing lens is large, namely, as the zoomlens is fed forwardly; and the strobe assembly 9 is moved to increasethe illumination. angle in the macro mode, in order to decrease theamount of light which reaches the subject. In the embodimentillustrated, strobe device 9 includes a fixed Fresnel Lens L6, a movableconcave reflector 59, and a xenon lamp 58 which can be moved along thedirection of the optical axis of the strobe. Alternately, a simplestrobe could be used in which the illumination angle would be fixed.Although such a strobe arrangement is possible, it is preferable to movethe lamp in the optical axis direction in accordance with movement ofthe zoom lens in order to optimize the quantity of light given to asubject during photography, dependent upon the position occupied by thephotographing optical system in the zoom lens.

B. Distance Measuring Device, i.e., Range Finder, and Camera MacroFunction

Before looking in a detailed fashion at the distance measuring device ofthe present invention and its relationship to the macro function of thecamera, the relationship between the distance of a subject from the twolens group zoom lens and the displacement or forward feed of the zoomlens will be now be discussed.

FIG. 12 illustrates a relatively simple construction for a two lensgroup zoom lens. In such a construction, the distance of the subject andthe displacement of the zoom lens have a relationship as follows:

    U=f1(2+X/f1+f1/X)+HH+Δ                               (1),

wherein

U equals the distance of a subject from the film plane;

f1 equals the focal length of the first lens group;

X equals the displacement of the zoom lens;

HH equals the principal point distance; and

Δ equals the distance between the focal point of the first lens groupand the focal point of the two lens group zoom lens.

From equation (1) it can be calculated that: ##EQU1##

FIG. 13 illustrates the relationship between the distance U of a subjectand the positional deviation (t) on a position detection element 4a,which forms a portion of the distance measuring device which detects thedistance of a subject from the film plane based upon the principle oftriangulation.

The triangulation distance measuring device includes a light emitter 3having a light source 3a and a light emitting lens 3b; and a lightreceiver 4 having a light receiving lens 4b and a position detectionelement 4a, e.g., a photo sensitive detector (hereinafter PSD). The raysof light emitted from light source 3a are reflected by the subject, andthe light reflected therefrom is received by position detecting sensor4a in order to detect the distance of the subject from the film plane F.Namely, the deviation (t) of the image on position detection sensor 4a,from a reference point represented by the position of an image of asubject at an infinite distance, relative to distance U of the subjectfrom film plane f, is given by the following equation:

    t=Lxf/(U-f-d)                                              (3),

in which

L represents the base length of the distance measuring device;

f represents the focal length of the light receiving lens; and

d represents the distance between film plane F and the focal plane ofthe light receiving lens.

The deviation (t) can be detected by the electric current, i.e., output,of position detecting sensor 4a in accordance with the quantity of lightreceived by position detecting sensor 4a, in a well known fashion. Thephotographing optical system of the camera is adjusted to form an imageon a focal point of the image plane in accordance with the outputsignal, i.e., electric current, of position detecting sensor 4a, basedupon equations (2) and (3), so that automatic focusing can be effected.The actuating or driving mechanism of the photographic optical system isnoted above.

It is necessary to shift the range of measurement of the subjectdistance by the distance measuring device towards a close subjectdistance side in order to achieve the macro function of the camera. Inthe macro mode, the photographing optical system is either partially orentirely displaced, from a standard picture taking position, towards thesubject to be taken, as is well known.

In the embodiment of FIG. 12, the first lens group of the photographinglens is moved forward, towards the subject over a predetermineddisplacement, in the macro mode, independently of (and beyond) thedisplacement effected by the automatic focusing device during normalphotography.

FIG. 14 represents one mechanism for shifting the range of measurementof the subject distance in the macro mode in accordance with the presentinvention. In FIG. 14, a relatively conventional prism P having an apexangle of δ is inserted in front of light receiving lens 4b in order toshift the range of measurement of the subject distance towards thesubject whose photograph is being taken. In other words, the zoom lenscamera system uses a pivotable prism or wedge which is adapted to bepositioned in front of light receiver 4.

Assuming, e.g., that the apex angle and the refractive index of prism Pare δ and n, respectively, the deviation t₁ of the image on positiondetecting sensor 4a, with respect to the subject distance U1, can beobtained as follows: firstly, the incident angle alpha of the rays oflight on the plane of prism P adjacent to the subject is determined bythe following equation:

    alpha=tan.sup.-1 {L/(U1-f-d)}+δ

Refraction angle beta of the rays of light which are incident upon prismP having an apex angle δ at the incident angle alpha is determined bythe following equation:

    beta=alpha-δ+sin.sup.-1  n sin {δ-sin/(alpha/n)}!, and, therefore γ=α-δ-β.

Accordingly, deviation t1 of the image on position detecting sensor 4awill be determined by t₁ =f×tanδ.

Subject distance Umf1, which is obtained when light which is coincidentwith the optical axis of light receiving lens 4b intersects the opticalaxis of light emitting lens 3b is determined as follows, provided thatthe thickness of prism P is negligible:

    Umf1=L/tan {sin.sup.-1 (n sin δ) -δ+f+d.

In one example, the present Applicants calculated the values of U, U1,t, t1, and t-t1, in a camera in which the photographing optical systemincluded a two lens group zoom lens, wherein: f1, i.e., the focal lengthof the first group, equals 24.68 mm; HH (i.e.,the principal pointdistance) equals 7.02 mm; delta, i.e., the distance between the focalpoint of the first lens group and the focal point of the zoom lens,equals 30.04 mm;

d, i.e., the distance between the film plane and the focal plane of thelight receiving lens, equals 6.292 mm; the displacement of the firstgroup at the macro setting equals 0.5502 mm; L, i.e., the base length ofthe distance measuring device, equals 30 mm; f, i.e., the focal lengthof the light receiving lens, equals 20 mm.; δ, i.e., the apex angle ofthe prism P, equals 2.826°; n, i.e., the refractive index of prism P,equals 1.483; the distance range which can be measured equals 0.973m˜infinity; and the number of steps of forward feeding movement of thezoom lens is 18, so that the range of 0.973 m˜6 m is divided into 17forward feeding motion steps of the zoom lens. The results of thesecalculations are illustrated in Table 1 hereinbelow. In thesecalculations, the distance range of 0.973 m˜6 m is shifted towards therange of 0.580 m˜1.020 m.

In Table 1 hereinafter, step 17-18 represents a shifting point at whichthe 17th step changes to the 18th step; similarly, the step 0-1represents a point of transfer between 0 and the first step.

                  TABLE 1                                                         ______________________________________                                        POSITIONS OF IMAGES ON THE POSITION DETECTING                                 SENSOR AT DIFFERENT SUBJECT DISTANCES                                         STEP NO.                                                                              U (m)   U .sub.1 (m)                                                                           t(mm) t.sub.1 (mm)                                                                          t.sub.1 - t (mm)                       ______________________________________                                        17-18   6.000   1.020    0.1004                                                                              0.1274  0.0270                                 17      5.154   0.996    0.1170                                                                              0.1423  0.0253                                 16      4.027   0.951    0.1500                                                                              0.1719  0.0219                                 15      3.310   0.911    0.1827                                                                              0.2013  0.0186                                 14      2.814   0.875    0.2153                                                                              0.2305  0.0153                                 13      2.450   0.841    0.2476                                                                              0.2595  0.0120                                 12      2.172   0.810    0.2797                                                                              0.2884  0.0087                                 11      1.952   0.782    0.3115                                                                              0.3170  0.0055                                 10      1.775   0.756    0.3432                                                                              0.3455  0.0023                                 9       1.628   0.132    0.3747                                                                              0.3738  -0.0009                                8       1.504   0.709    0.4059                                                                              0.4018  -0.0041                                7       1.399   0.688    0.4369                                                                              0.4298  -0.0072                                6       1.309   0.668    0.4678                                                                              0.4575  -0.0103                                5       1.230   0.650    0.4964                                                                              0.4850  -0.0134                                4       1.161   0.633    0.5288                                                                              0.5124  -0.0165                                3       1.100   0.616    0.5591                                                                              0.5396  -0.0195                                2       1.045   0.601    0.5891                                                                              0.5666  -0.0225                                1       0.996   0.587    0.6189                                                                              0.5934  -0.0255                                0-1     0.973   0.580    0.6338                                                                              0.6068  -0.0270                                U .sub.mfl = 1.283 m                                                          ______________________________________                                    

As can be seen from Table 1, an image deviation of 0.027 mm occurs atthe position detecting sensor 4a at the two extremities of the range ofmeasurement of the subject distance which can be measured, as a resultof compensation by prism P. Such a deviation corresponds substantiallyto about 1 step, in the sense of the number of feeding steps of the zoomlens. Accordingly, it is not possible to move the photographic lens intoa correct focal point by directly controlling displacement of thephotographing optical system in response to the output of positiondetecting sensor 4a, thus resulting in an "out of focus" situation.

In other words, it is impossible to completely compensate for deviationin the images by using only prism P, since the rate of change ofdeviation t1 of the image on position detecting sensor 4a with respectto subject distance U1 cannot be varied by prism P. The prism begins tocompensate for the image deviation, but cannot alone do so.

In view of such results, the present inventors have found that completecompensation of such deviation can be achieved if the rate of deviationt1 is adjusted by multiplying this rate by 1.1130 (calculated bydividing 0.5334 by 0.4794), which equals the change in t from step 0-1to step 17-18 divided by the change in t1 between step 0-1 and step17-18, since decreases in the deviations t and t1 between steps 17-18and 0-1 are 0.5334 mm and 0.4794 mm, respectively. To this end, in thepresent invention, a macro mode compensating optical element is adaptedto be selectively moved in front of the distance measuring opticalsystem only when the camera is placed in the macro mode, in order tooptically extend the base length between the light emitter and the lightreceiver of the distance measuring optical system, and in order tointersect the optical axis of the light emitter and the optical axis ofthe light receiver with a finite distance. Further, in this embodiment,an actuating mechanism is provided for moving the macro compensatingoptical element in front of the light receiver in coordination withtransfer or movement of the photographing optical system, i.e., the zoomlens, from the normal photographic mode to the macro mode, as discussedin detail hereinafter.

FIG. 9 illustrates an optical arrangement of the distance measuringdevice when in the macro mode, in the automatic focus camera of thepresent invention. In this figure, macro compensating element 4ecomprises a prism 4c and a mask or frame 4d, rather than only theoptical wedge of FIG. 14. Element 4e is moved in front of lightreceiving lens 4b of the distance measuring device when the camera is inthe macro setting. In the normal photographic mode, element 4e isretracted away from the optical axis of light receiving lens 4b.

Prior to discussing the mechanical structure which is adapted to actuatethe compensation element 4e, the actual construction of the macrocompensating element 4e and the reasons why measurement accuracy can beimproved or increased in the macro mode will be described in detail. Theelement includes a prism 4c which is adapted to optically extend thebase length of the distance measuring device and to refract rays oflight which enter the prism.

FIG. 10 illustrates in detail prism 4c, mask 4d, and light receivinglens 4b. FIG. 11 is a front elevational view of FIG. 10; and both ofthese figures illustrate how mask or frame 4d is capable of interceptingrays of light out of the path of light approaching the prism. Mask 4dincludes a front opening 4f which is shown in the form of a generallyrectangular, elongated slot, on the (front) side of the frame locatedmost closely adjacent to the subject being photographed, and a rearopening 4g (see FIG. 10) on the side of the frame or mask most closelyadjacent to light receiving lens 4b. Opening 4f is in the form of a slitspaced from optical axis O of light receiving lens 4b by a distance (1)which is measured on the opposite side of the optical axis from lightemitting lens 3b. Rear opening 4g is also in the form of a elongatedslit, which is substantially located along the optical axis O of lightreceiving lens 4b.

When prism 4c, together with mask 4d, move in front of light receivinglens 4b, i.e., when the camera is in the macro mode, a first lens groupof the photographic lens is fed forwardly by a constant displacement,independently of the displacement of the lens which is fed forwardlyduring the normal photographic mode by the automatic focusing device. Asbest seen in FIGS. 9 and 10, when prism 4c is located in front of lightreceiving lens 4b, the range of measurement of the distance of thesubject can be shifted to the macro mode range. Prism 4c serves to movelight incident thereon in a parallel fashion, over a displacement (1) inthe direction of the base length, so that base length L can be opticallyextended to equal the distance (L+1).

Assuming that the angle and the refractive index of prism 4c are δ₁, andn, respectively, and that the parallel displacement of light by prism 4cis represented by the distance (1), deviation t2 of the image onposition detecting element 4a, as viewed with respect to the subjectdistance U2, can be obtained as hereinafter detailed.

The incident angle of light on the plane of prism 4c which is adjacentto the subject is provided by the following equation:

    alpha.sub.1 =tan.sup.-1 {(L+1)/(U2-f-d)}+δ.sub.1.

This equation indicates that the base length of the triangulationdistance measuring device is extended from L to (L+1) by the insertionof prism 4c in front of the light receiving lens 4b. The refractionangle beta₁ of light which is incident upon a prism having an angle δ₁,which light is incident upon the prism at an incident angle of alpha₁,is calculated in accordance with the following equation:

    beta.sub.1 =alpha.sub.1 -δ.sub.1 +sin.sup.-1  n sin {δ.sub.1 -sin (alpha.sub.1 /n}!,

and, therefore:

    δ.sub.1 =alpha.sub.1 -δ.sub.1 -beta.sub.1.

Accordingly, deviation t2 of the image on position detecting sensor 4ais equal to f×tan δ₁, i.e., t2=F×tan δ₁.

The subject distance Umf2 which is obtained when light coincident withthe optical axis of light receiving lens 4b intersects the optical axisof light emitting lens 3b is yielded by using the following equation,provided that the thickness of prism 4c is negligible:

    Umf2=(L+1)/tan {sin.sup.-1 (n×sin δ.sub.1)-δ.sub.1 }+f+d.

Table 2 hereinafter illustrates the results of the calculations in whichthe distance measuring device of FIGS. 10 and 11 has been applied to aphotographing lens satisfying the same basic criteria as those mentionedwith respect to the embodiment of FIG. 14, i.e., namely that:

(a) The photographic lens is a 2-group lens;

(b) f1, i.e., the focal length of the first group, equals 24.68 mm;

(c) HH, i.e., the principal point distance, equals 7.02 mm;

(d) delta, i.e., the distance between the focal length of the first lensgroup and the focal length of the zoom lens, equals 30.04 mm;

(e) d, i.e., the distance between the film plane and the focal plane ofthe light receiving lens, equals 6.292 mm;

(f) the displacement of the first lens group in the macro setting equals0.5502 mm;

(g) L, i.e., the base length of the distance measuring device, equals 30mm;

(h) f, i.e., the focal length of the light receiving lens, equals 20 mm;

(i); δ₁, i.e., the angle of prism 4c, equals 3.39°;

(j) n, i.e., the refraction index of the prism, equals 1.483;

(k) (l), i.e., the distance representing the parallel displacement ofthe rays of light, equals 3.39 mm;

(l) the range of measurement of the distance of the subject which can bemeasured equals 0.973 m˜infinity;

(m) the number of steps of forward feeding movement of the zoom lens is18;

(n) the range of 0.973 m˜6 m is divided into 17 steps; and

(o) the photographic range of 0.973 m˜6 m is shifted into the range of0.580 m˜1.020 m.

                  TABLE 2                                                         ______________________________________                                        POSITIONS OF IMAGES ON THE POSITION DETECTING                                 SENSOR AT DIFFERENT SUBJECT DISTANCES WITH THE                                MACRO COMPENSATION ELEMENT OF FIGS. 9, 10 AND 11                              STEP NO.                                                                              U (m)   U .sub.2 (m)                                                                           t(mm) t.sub.2 (mm)                                                                          t.sub.2 - t (mm)                       ______________________________________                                        17-18   6.000   1.020    0.1004                                                                              0.1005  0.0001                                 17      5.154   0.996    0.1170                                                                              0.1171  0.0001                                 16      4.027   0.951    0.1500                                                                              0.1500  0                                      15      3.310   0.911    0.1827                                                                              0.1827  0                                      14      2.814   0.875    0.2153                                                                              0.2152  -0.0001                                13      2.450   0.841    0.2476                                                                              0.2475  -0.0001                                12      2.172   0.810    0.2797                                                                              0..Z796 -0.0001                                11      1.952   0.782    0.3115                                                                              0.3115  0                                      10      1.775   0.756    0.3432                                                                              0.3432  0                                      9       1.628   0.732    0.3747                                                                              0.3746  -0.0001                                8       1.504   0.709    0.4059                                                                              0.4059  0                                      7       1.399   0.688    0.4369                                                                              0.4369  0                                      6       1.309   0.668    0.4678                                                                              0.4677  -0.0001                                5       1.230   0.650    0.4984                                                                              0.4984  0                                      4       1.161   0.633    0.5288                                                                              0.5288  0                                      3       1.100   0.616    0.5591                                                                              0.5591  0                                      2       1.045   0.601    0.5891                                                                              0.5891  0                                      1       0.996   0.587    0.6189                                                                              0.6190  0.0001                                 0-1     0.973   0.560    0.6338                                                                              0.6338  0                                      U .sub.mf2 = 1.283                                                            ______________________________________                                    

It should be clearly understood from Table 2 that the deviation of theimages on the position detecting sensor 4a at different steps betweenthe normal photographic mode and the macro mode will therefore be within±0.000 mm. This is represented by the value t₂ -t in the last column inTable 2. Accordingly, it is possible to almost completely form images atthe focal point by adjusting the photographic optical system inaccordance with the output of the position detecting sensor 4a. Table 2illustrates that prism 4c can optically extend the base length, which isnormally 30 mm in a normal photography camera mode, in the macro mode sothat it will be 1.113 times the normal base length, i.e., the baselength will be 33.39 mm when the camera is in its macro mode; as aresult, displacement of position detecting sensor 4a can be increased bya factor of 1.113.

In operation, it is possible to automatically focus the camera withinany zooming range, including the macro setting of the camera, byactuating previously discussed shutter unit 23 in accordance with theoutput signals, i.e., the measurement data, which are sent by positiondetecting sensor 4a. Specifically, when driving pulses are applied tothe pulse motor of shutter unit 23 in accordance with the measurementdata which has been received from detecting sensor 4a, a lens actuatingor feeding lever 23a, as seen in FIG. 8, rotates over an anglecorresponding to the driving pulses which it has received in order torotate front lens frame 24 together with it. As a result of thisrotation of front lens frame 24, the front lens element group L1 ismoved along the direction of the photographing optical axis, via theaction of helicoid 25, in order that focusing of the photographic lensassembly will be automatically effected.

Lens barrel block 1 rotates cam ring 14 when zooming motor 5 is driven.Rotation of cam ring 14 causes roller 17 of front frame 16 to engage theextreme macro position fixing section 20g of cam groove 20, i.e., rollermoves into section 20g from macro transfer section 20f of cam ring 14,so that front lens element group L1 will be fed further forwardly tomove into position for macro mode operation of the camera.

As clearly seen in FIGS. 1 and 2, macro compensating element 4e issecured to a free end of a flexible compensation or correcting flag 42,which is pivoted at its base end to camera base plate 6 via a shaft 41located below light receiver 4. Flag 42 is normally retained in asubstantially straight position when no external force is applied to theflag, and is elastically deformed whenever an external force is appliedto the flag. Also attached to shaft 41, and having a pointed surfacedirected away from the flag, is a projection 43, which can either beformed integrally with the flag and attached to shaft 41, or which canbe formed separately from the flat and attached to shaft 41 at a centralbore of the projection. The macro compensating element 4e iscontinuously and rotatably biased into a retracted position in which itis retracted away from the optical axis of light receiver 4 by a tensionspring 46, as illustrated in FIG. 2. As seen in FIG. 2 and (better) inFIG. 1, cam ring 14 includes a projection 44 on sector gear 15 (or onthe cam ring) which engages flag projection 43 in order to move macrocompensating optical element 4e into the optical axis of the distancemeasuring device and in front of light receiver 4 whenever the cam ring14 rotates to the macro setting position. As shown in FIG. 1, asubstantially semi-cylindrical recess (or other recess configuration)44a is provided on the gear 15 adjacent to the camming surface orprojection 44. This recess is provided to facilitate the pivoting orrotating motion of flag projection 43 as the cam ring rotates. In otherwords, recess 44a is necessary to facilitate turning movement of theprojection and hence pivoting or rotating motion of optical element 4einto the position illustrated in dotted lines in FIG. 2, in front oflight receiver 4. Alternately, ring 14 or gear 15 can be formed with asmaller diameter in order to provide sufficient pivoting room forprojection 43. Camming projection 44, which effects, via its engagementwith projection 43, rotational or advancing motion of macro compensatingoptical element 4e, is positioned and configured so that the opticalelement will be rotated slightly past the position in which the elementwould be aligned with the optical axis of light receiver 4. However, theflat end of the element 4e which most closely approaches support plate6e which is integrally attached to base 6, is adapted to engage the lefthand side surface of plate 6e (as seen in FIG. 2) via a shock absorbingnub or button 4g, shown in both FIGS. 1 and 2. Accordingly, overrotational motion of element 4e which is effected by projection 44 willbe absorbed both by the flexible flag 42, which is formed from aresilient plastic, rubber, or other resilient material and/or theprovision of nub 4g, which will serve to engage the side edge of plate6e.

Thus, when cam ring 14 moves into the macro setting position, the macrocompensating optical element 4e can automatically be brought intoalignment with the optical axis of the light receiver, into a positionin front of the light receiver, in order to optically extend the baselength between the light emitter 3 and the light receiver 4.

C. Finder Optical System

The finder optical system is best illustrated in FIGS. 1 and 15-20.

The finder optical system is designed not only to vary magnificationbetween a wide field of view with a small magnification, and a narrowfield of view with a large magnification, in accordance with the zoomingoperation of the photographing lens system, but also to provide a fieldof view having less parallax when the camera is used in its macro mode.

One significant feature of the present invention is that the finderoptical system is capable of automatically moving in association withboth zooming of the photographic lens and movement of the photographiclens into a macro setting in order to satisfy all of the requirements ofa finder system as set forth immediately above. While conventionalfinders appear to provide a plurality of bright frames with differentsizes in the field of view of the finder, this is not a satisfactorysolution to the problems noted above, e.g., the use of such frames alonewill not minimize parallax in a macro operational mode such as that usedin the present camera.

Under such circumstances, and in accordance with the present invention,a finder optical device is provided in a lens shutter type of camerahaving a zoom lens which essentially comprises an improved invertedGalilean finder. In other words, the finder optical system of thepresent invention includes a first lens group having a negativerefracting power which comprises a positive lens in the form of a fixedlens L3 and a movable negative lens in the form of a variable power lensL5, a second lens group having a negative lens L4-1 which is one lens ina fixed eyepiece group L4, and a third lens group having a positiverefracting power lens L4-2 which defines a second lens in the fixedeyepiece lens group L4. A prism P1 is adapted to be selectively movedbetween the positive lens L3 and the negative lens L5 of the first lensgroup in order to refract rays of light towards the optical axis. Thenegative lens L5 of the first group can be displaced from a positionadjacent to the subject towards a position which is adjacent to aphotographer's eye in order to vary the magnification from a wide fieldof view having a small magnification to a narrow field of view having alarge magnification. Prism P₁, selectively brought into alignment withthe optical axis of the finder optical system, serves to decrease theparallax when the photographic optical system is in the macro settingand when the negative lens L5 of the first group moves closest to theeye of the photographer along the optical axis.

The bright frames which are illustrated in dashed lines in FIG. 52define the photographing ranges and are applied to the face of the lensof the third group which is closest to the subject, i.e., on the lefthand face A of stationary eyepiece lens L4-2 in FIGS. 15A, 16A, 17A,18A, 19A and 20A, respectively. These yellow frames, which are placed onlens surface A comprise a central autofocus spot (to be positioned onthe main portion of a photographic subject), a large picture area frame(for ordinary photography using the zoom lens), and a smaller parallaxcorrection frame (used since the picture area will slightly narrow inthe macro mode). Further, face B of the second lens group L4-1 which ismost closely adjacent to the eye of a photographer, is formed from asemi-transparent material, so that a virtual image of the bright frameswhich are formed by the semi-transparent face can be enlarged and viewedthrough the positive lens of the third lens group L4-2.

The yellow bright frames are positioned on the front surface of thefixed eye piece lens L4-2 by, e.g., sputtering; and the rear surface ofthe eyepiece lens element L4-1, i.e., surface B or r6, can be in theform of a semi-transmissive, semi-reflective concave mirror. Light raysemitted from (i.e., reflected by) the bright frames are reflectedrearwardly by concave surface R6 and are focused on the viewers eye. Theeye recognizes enlarged false images of the frames in a position in thefar foreground, which images are formed via the optical effect of lensesL4-1 and L4-2.

The negative lens L5 of the first group is movable, as noted above, sothat it will move from a position which it is located adjacent to thesubject into a position in which it is more closely adjacent to the eyeof a photographer, in order to increase the focal length of thephotographic optical system during the normal zooming operation, so thatmagnification can be varied from a wide field of view having a smallmagnification to a narrow field of view having a large magnification.When a picture is taken in the macro (beyond telephoto) mode with anarrow field of view and large magnification, a prism is insertedbetween the movable lens L5 and stationary lens L3 in order to decreaseparallax, so that light will be refracted towards the location of theaxis of the photographic optical system.

Enough room is provided for the prism to pivot upwardly for macrofocusing, i.e., thereby creating a need to move the lens L5 a relativelylarge distance, as shown in FIGS. 16A, 17A, 19A and 20A, in order toinsert the prism P1 therein in a pivotable or rotatable fashion.

On advantage of the system is that it incorporates only a single movinglens L5, rather than zooming a plurality of lenses or the entire finderoptical lens system and having to thereafter compensate for such zoomingmovement of all of the lenses. This serves to simplify the zooming camplate structure, as movement of only a single lens will suffice tochange the magnification of finder image.

The fixed viewing frames, as shown in FIG. 52, are provided in order toavoid having to take a viewing adjustment. The two rear eyepiece lensgroups L4-1 and L4-2 which include the frames are fixed, and thecurvatures of their respective surfaces are controlled so that thereflected frames will have a desired magnification which is compatiblewith the image magnification over the entire range of zooming operationof the photographic lens.

The apex angle or angles of the selectively insertable prism are definedby the resultant angles in the horizontal and vertical directions, inaccordance with the positions of the optical finder system and thephotographic optical system. The prism can be a single wedge prism, orcan be a double wedge shaped prism, as illustrated in FIGS. 53A, 53B,and 53C, which illustrate a double wedge prism P1' which is advantageousbecause it is capable of bending light downwardly and rightwardlytowards the optical axis of the photographic optical system.

As illustrated in FIGS. 53, double wedge prism P1 has a surface whichincreases, when viewed from the top in the direction of arrow A (seeFIGS. 53A and 53B) and which also increases from the left hand to theright hand direction, as viewed from the front of the camera from thephotographing optical axis, and as shown by arrow B (FIGS. 53A and 53C).In the example illustrated, the angle φH can be 2.8°, the angle φV canbe 4.2°, the angle φH' could be 4.2°, and the angle φV' could be 5.0°.

The wedge prism is adapted to be inserted between the first convexsingle lens element L3 and the movable concave single lens element L5 ina rotatable fashion. This permits the finder unit to be made compactlyand allows the prism to be inserted between these two elements. Theviewing distance of the false image of an object and the bright framesremain stationary throughout the zooming range of the photographic lens,and parallax compensation is provided by moving the prism between thelenses in the macro or close up picture taking mode. The viewingmagnification or size of the bright frame images is also maintainedconstant throughout the zooming range of the photographic lens, as wellas in the macro setting, due to the placement of the bright frames onthe stationary lens element L4-2. The distance between the eye of aviewer and the image distance, i.e., the diopter of the finder,virtually does not vary, because the zooming concave lens element movesover an image magnification of 1×, or, i.e., is life size.

Parallax compensation in the macro or close up picture taking mode iseffected by positioning the wedge prism between the lens elements, aswell as by the use of the compensation framing marks illustrated in FIG.52 (which is the normal means of parallax compensation in a closefocusing mode in viewfinder type cameras). The edges of the wedge prismare tinted green to highlight the frame that illustrates thephotographic area in the macro or close-up mode.

Theoretically, the prism could be located in front of the first lensgroup; however, by so arranging the prism, it would increase the overallsize of the finder optical system. The prism cannot, however, be locatedbetween the second and third lens groups, because if it were insertedbetween these groups, the positions of the bright frame and of thevirtual image of the subject could vary in accordance with movement ofthe prism. However, when the prism is retractably inserted between thepositive lens and the negative lens of the first lens group, as is thecase in the present invention, the prism is free from such problems, andvirtually no change in diopter power to the virtual image of the subjectwill occur.

Several examples of a finder optical system formed in accordance withthe present invention will now be discussed:

EXAMPLE 1

FIGS. 15A, 15B, 16A, 16B and 17A, 17B illustrate different positions ofa first embodiment of a finder device formed in accordance with thepresent invention. FIG. 15A illustrates the finder optical system whenit is providing a wide field of view with a small magnification; FIG.16A illustrates this finder system when it is providing a narrow fieldof view with a large magnification; and FIG. 17A illustrates the findersystem whenever it is providing a narrow field of view with largemagnification and when it is in the macro mode, respectively. FIGS.15B-D, 16B-D and 17B and C respectively, are views illustrating theaberrations of the finder lens system in the positions of FIGS. 15A, 16Aand 17A, respectively.

This finder optical system includes a positive single lens L3 and anegative single lens 15 which form the first lens group; a negativesingle eyepiece lens L4-1 which forms the second lens group; and apositive single eyepiece lens L4-2 forming the third lens group;together with a selectively positionable prism P1. Among all of theseoptical elements, only the negative single lens L5 is movable along thedirection of the optical axis, and prism P1 is selectively movable intoalignment with this optical axis; all of the other lenses remainstationary.

Tables 3 and 4 which follow illustrate the curvatures r, the distancesd, the refractive indexes Nd and Abbe's numbers νd of the opposite sidefaces of optical elements L3, L5, L4-1, L4-2, and P1 (Table 4 only),respectively. As shown in the following tables 3 and 4, each of featuresr, d, Nd and νd are designated by any one of numbers 1-8 and 1-10,respectively, as viewed from the side of the positive single lens L3which is closest to the subject, i.e., from the left hand portion of thefigures towards the eye or right hand portion of the figures.

Table 3 represents the position of the lens when it is in its wide fieldof view, small magnification position (0.38×) and when it is in itsnarrow field of view, large magnification position (0.70×), and Table 4illustrates the position of the lens when it is in the macro mode. Theapex angles of prism P1 used in this mode, when it is in a double wedgeprism are, e.g., 2.8° in horizontal section and 4.2° in verticalsection.

The bright frame which defines the picture taking range is applied tosurface A of the positive single lens L4-2 of the third lens group whichis most closely adjacent to the subject being photographed, and thesurface B of the negative single lens L4-1 of the second lens groupwhich is most closely adjacent to the photographers eye issemi-transparent. As a result, a virtual image of the bright frameapplied to face A of the positive single lens L4-2 is formed andreflected by face B, and is thereafter enlarged and viewed through thepositive single lens L4-2, again as discussed previously.

                  TABLE 3                                                         ______________________________________                                        No.    r           d           Nd    νd                                    ______________________________________                                        1      30.800       4.50       1.49186                                                                             57.4                                     2      -2221.231    0.50(0.38×) ˜                                                    15.80(0.70×)                                         3      55.555       1.21       1.49186                                                                             57.4                                     4      9.680       18.30(0.38×) ˜                                                     3.00(0.70×)                                         5      -8.327       1.00       1.60311                                                                             60.7                                     6      50.845       7.33                                                      7      ∞      2.23       1.60311                                                                             60.7                                     8      -11.780                                                                ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        No.      r        d           Nd    νd                                     ______________________________________                                        1        30.800   4.50        1.49186                                                                             57.4                                      2        -2221.231                                                                              1.70                                                        3        ∞  2.70        1.49186                                                                             57.4                                      4        ∞  11.40                                                       5        55.555   1.21        1.49186                                                                             57.4                                      6        9.680    3.00                                                        7        -8.327   1.00        1.60311                                                                             60.7                                      8        50.845   7.33                                                        9        ∞  2.23        1.60311                                                                             60.7                                      10       -11.780                                                              ______________________________________                                    

EXAMPLE 2

FIG. 18A illustrates a second embodiment of the finder optical system inits wide field of view, small magnification position; FIG. 19Aillustrates this embodiment in its narrow field of view, largemagnification position; and FIG. 20A illustrates this finder opticalassembly embodiment in its narrow field of view, large magnification,macro mode position; and FIGS. 18B-D, 19B-D and 20B and C respectively,illustrate the aberrations in the finder lens system in the threedifferent positions illustrated in FIGS. 18A, 19A and 20A, respectively.In this second embodiment of the finder optical device, the lens systemis different from that in the first embodiment as discussed in example1, insofar as the third lens group comprises two lenses in the form ofpositive lenses L4-2 and L4-3.

Tables 5 and 6 illustrate the curvatures r, distances d, refractiveindexes Nd, and Abbe's numbers νd, for all of the elements of the secondembodiment of the finder lens system, which tables are similar to Tables3 and 4 previously discussed with respect to the first embodiment of thefinder optical system. In Table 5, which represents the wide field ofview, small magnification (0.35×) position of the system, and the narrowfield of view, large magnification (0.648×) position of the system, andin Table 6, which represents the system when in the macro mode, the apexangle of prism P1 is 3.0° in the horizontal direction and 5.0° in thevertical direction, e.g. The bright frame which defines the photographicrange is again applied to face A of the positive lens L4-2 of the thirdgroup, and face B of the negative single lens L4-1 of the second groupis again semi-transparent, as in the first embodiment of the findersystem.

                  TABLE 5                                                         ______________________________________                                        No.    r           d           Nd    νd                                    ______________________________________                                        1      25.800       4.50       1.49186                                                                             57.4                                     2      -190.341     0.50(0.35×) ˜                                                    11.89(0.648×)                                        3      65.200      1.50        1.49186                                                                             57.4                                     4      8.081       14.39(0.35×) ˜                                                     3.00(0.646×)                                        5      -7.056      1.00        1.67003                                                                             47.3                                     6      34.700      5.37                                                       7      ∞     2.93        1.60311                                                                             60.7                                     8      -12.536     0.30                                                       9      -30.259     2.23        1.49186                                                                             57.4                                     10     -15.420                                                                ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        No.      r        d           Nd    νd                                     ______________________________________                                        1        25.800   4.50        1.49186                                                                             57.4                                      2        -190.341 9.42                                                        3        ∞  2.00        1.49186                                                                             57.4                                      4        ∞  0.47                                                        5        85.200   1.50        1.49186                                                                             57.4                                      6        8.081    3.00                                                        7        -7.056   1.00        1.67003                                                                             47.3                                      8        34.700   5.37                                                        9        ∞  2.93        1.60311                                                                             60.7                                      10       -12.538  0.30                                                        11       -30.259  2.23        1.49186                                                                             57.4                                      12       -15.420                                                              ______________________________________                                    

As illustrated in FIG. 17A, the finder optical device of the presentinvention preferably satisfies the following conditions:

    0.3<dP<0.5;                                                (1)

    f1+<1.8; and (3) 0.45<f3/LD<0.7;                           (3)

wherein:

LD=the total length of the finder;

dP=the distance between the face of lens L3 which is most closelyadjacent to prism P1 and the face of lens L5 which is most closelyadjacent to prism P1;

f1+=the focal length of the positive lens of the first lens group, andf3=the focal length of the third lens group.

These criteria are useful and helpful to enable prism P1 to beretractably inserted between the movable lens L3 of the first lens groupand the negative lens L5 of the first lens group and to minimize theeffective diameter of the prism when it is brought into alignment withthe optical axis.

The first condition, i.e., 0.3<dP<0.5 is based upon the fact that if thevalue of dP exceeds the noted upper limit, the effective diameter of thelens L3 will become large, making it difficult to provide a compactcamera as does the present invention; to the contrary, if the value ofdP was <0.3, it would become extremely difficult to smoothly and easilyrotate prism P1 so that it would come into alignment with, and becapable of retracting away from, the optical axis in a position betweenlenses L3 and L5.

Conditions 2 and 3, in which f1+<1.8, and 0.45 f3/LD<0.7, are providedto minimize the effective diameter of prism P1. The second criterianoted above is substantially equivalent to setting or establishing thefocal length FR of the lens system which is positioned rearwardly ofprism P1 when the prism is in alignment with the finder optical axis.Namely, if f1+ exceeds its noted upper limit of 1.8, the effectivediameter of the prism will become large, thereby resulting in difficultyin realizing a compact prism and finder.

Condition three is basically equivalent to a requirement for the thirdlens group located rearwardly of the prism. Namely, if f3/LD is lessthan the lower limit of 0.45, the tolerance of the system will becomequite small. To the contrary, if the value of f3/LD exceeds the upperlimit of 0.7, the effective diameter of the prism will increase.

The values of dP, f1+, and f3/LD in the first and second embodimentsabove will now be listed; all of these values are set to satisfyconditions 1, 2 and 3 noted above.

    ______________________________________                                                 First Embodiment                                                                        Second Embodiment                                          ______________________________________                                        dP         0.45        0.36                                                   f1+        1.76        1.42                                                   f3/LD      0.56        0.49                                                   ______________________________________                                    

D. Drive Mechanism for the Finder and Strobe Devices

The driving mechanism which serves to actuate finder optical assembly 8and strobe assembly 9 is best illustrated in FIGS. 21-30.

A mother plate 60 is attached to a finder block 54 which is mounted tobase plate 6 via horizontal support plate extension 6b. The mother plateis provided with guide pins 62 integrally attached to the mother plateand which are adapted to fit within a substantially linear guide groove61 of cam plate 53. Sliding motion of cam plate 53 is in the lateraldirection, with respect to the optical axis of the camera, and isrestricted by the engagement between guide grooves 61 and guide pins 62;and a guide projection or flange 60a (shown in both FIGS. 21 and 22) isformed integrally with mother plate 60 and serves to prevent cam plate53 from floating or moving away from the front surface of the motherplate, particularly at the front end of cam plate 53 where the flangeengages the cam plate.

Finder mother plate 60 includes a variable power lens guide groove 63, adeflection prism guide groove 64, and a strobe assembly guide groove 65.Each of these guide grooves extends parallel to the photographic opticalaxis of the camera. A guide projection 66a of variable finder lens frame66, which carries the variable finder power lens group LS, is fittedwithin variable power lens guide groove 63. Guide projection 67a ofdeflection prism actuating plate 67 is slidably positioned or fittedwithin deflection prism guide groove 64; and guide projection 68a ofstrobe assembly case 68, which casing has a concave reflector 59attached thereto, is fitted or positioned within strobe guide groove 65.

Variable power lens frame 66, deflection prism actuating plate 67, andstrobe assembly case 68, together move in a direction which is parallelwith respect to the optical axis, along the respective guide grooves.Guide projections 66a, 67a, and 68a are provided with driven 69, 70 and71, which fit within the variable power cam groove 55, the parallaxcompensating cam groove 56, and the strobe cam groove 57, respectively.Accordingly, when cam plate 53 moves laterally, variable power lensframe 66, reflection prism actuating plates 67, and strobe case 68 movealong the respective camming grooves 55, 56 and 57.

The sections of the variable power cam groove 55, parallax compensatingcam groove 56, and strobe cam groove 57 correspond to sections ofzooming cam grooves 20 and 21 of cam ring 14 which have been illustratedin FIG. 7 and described with respect thereto. Specifically, the variablepower cam groove 55 includes an extreme wide angle fixing section 55a, avariable power section 55b, and an extreme telephoto fixing section 55c,with the angles φ₁, φ₂ and φ₃, respectively, of these three sectionscorresponding to the similar angles in the cam ring FIG. 7. The parallaxcompensating cam groove 56 includes a non-projecting section 56a, aprojecting movement section 56b, i.e., a forward feed section used forthe macro mode, and a projected position fixing section 56c, i.e., anextreme macro fixing section. Strobe cam groove 57 includes an extremewide angle fixing section 57a, a variable power section 57b, an extremetelephoto fixing section 57c, a macro feeding section 57d, and anextreme macro fixing section 57e. The relationship between cam grooves55, 56 and 57, and zooming cam grooves 20 and 21, is best illustrated inthe schematic or plan view illustrated in FIG. 44.

The variable power lens frame 66 which supports the variable power lensgroup L5 is movably supported along guide face 54a of finder block 54 sothat frame 66 will hang therefrom, as best illustrated in FIG. 25. Theframe can be formed, e.g., from a resin which can slide with respect tothe finder block in a substantially frictionless fashion. When variablepower lens frame 66 moves along variable power cam groove 55,magnification of the finder optical system, including lens group L3, eyepiece group L4, and variable power lens group LS, will vary, so that thephotographic range over which lens barrel block 1 moves will besubstantially coincident with the field of view of the finder.

The deflection prism actuating plate 67 is illustrated in FIGS. 26-28,and is hereinafter described in greater detail.

Deflection prism P1, which is formed of synthetic resin, is rotatablysupported by finder block 54 via two lower opposed prism support pins 74of the prism. These supporting pins include torsion springs 75 whichsurround them, with one end of each spring bearing against a respectiveabutment 76 which abutments are provided along the side faces ofdeflection prism P1, so that the deflection prism will be continuouslybiased into a position in which the prism P1 moves into alignment withthe optical axis of finder lenses L3-L5. Abutment 76 are located inarc-shaped grooves 79 formed in finder block 54., as best illustrated inFIGS. 26-28. The deflection prism actuating plate 67 is held betweenfinder block 54 and a guide plate 80 (see FIG. 25) connected to finderblock 54 so that a guide pin 81 which is positioned on the side face offinder block 54 will fit within linear guide groove 82 of guide plate80.

Position restricting abutments 76 on the prism can be engaged by a stopsurface 77 and a guiding surface 78 of deflection prism actuating plate67; further, the prism abutments 76 can come into contact with an endsurface of the groove 79 in plate 67 (see FIG. 27). Deflection prismactuating plate 67 serves to retract the deflection prism from theoptical path of lenses L3-L5, against the bias of springs 75, when pin70 is located in the non-projection section 56a of parallax compensatingcam groove 56, insofar as the rotation preventing face 77 of the platewill move into engagement with abutment 76 (see FIG. 26). When pin 70moves into the projecting movement section 56b, guide surface 78 willmove into a butting contact with abutment 76, so that deflection prismP1 will rotate into a position in which it is in alignment with thefinder system optical axis with the help of torsion spring 75. Duringsuch movement, abutments 76 move on and along face 78, and deflectionprism P1 will gradually move into the optical path, as illustrated inFIGS. 27 and 28, so that the optical path of the finder will bedeflected downwardly by prism P1, as illustrated by the arrow in FIG.28. As a result of this movement, a subject which is otherwise locatedbelow the finder optical axis will come into the camera field of view,and parallax in the macro mode of the camera will be decreased. It iseven further decreased, as noted above, when a double wedge prism (FIG.53A) is used to deflect the finder optical axis downwardly and(rightwardly) towards the optical axis of the photographing opticalsystem.

A guide block 85 is provided along the side face of strobe case 68 andis fitted within a linear guide groove 84 which is parallel to theoptical axis of the camera which is formed in guide plate 80, asillustrated in FIG. 30. Further, height adjusting pins 86 (see FIGS. 23and 29) are provided on the upper and lower faces of strobe case 68 andare adapted to prevent the strobe case from falling downwardly. Thestrobe case 68 moves along strobe cam groove 57 when cam plate 53 movesin the lateral direction. Variable power section 57b of strobe camgroove 57 is adapted to move xenon lamp 58 rearwardly, away from Fresnellens L6. Rearward movement of the xenon lamp 58 causes the illuminationangle of light emitted from Fresnel lens L6 to decrease so as tosubstantially increase the guide number in accordance with an increasein the focal length. To the contrary, in macro feeding section 57d, theillumination angle is increased, and the guide number is thereforesubstantially decreased in the macro mode.

E. Barrier, i.e., Lens Cap, Mechanism

The barrier lens cap mechanism is best illustrated in FIGS. 6, 8 and31-34.

Barrier mechanism 30 opens and closes a pair of barriers 31, (see FIG. 8) which are located forwardly of the front lens element group L1 of thephotographic (zooming) lens system, and which are closed with theassistance of rotational force which is produced when cam ring 14rotates within retracting or storing cam section 20b (see FIG. 7) inwhich the lens is collapsed.

FIG. 31 and 32 illustrate a first embodiment of the barrier mechanism.In this embodiment, barrier mechanism 30 opens and closes a photographicopening 22b at the opening of frame 22 via pivoted barrier elements 31.The barrier elements are pivoted, via pins 32, in a substantiallysymmetrical fashion with respect to the photographic opening 22b of thefront lens group support frame 22.

Barriers 31 are disposed in a symmetrically opposite position withrespect to each other and include respective barrier plate portions 31awhich can be moved. so as to project into the path of the photographingoptical axis, as well as driving arm portions 31b which are positionedon the opposite sides of the barriers from the side on which barrierplate portions 31a are located. Driving arm portions 31b are generallyattached to the inner front surface of barrier assembly 30 by pins 33.Driving arm portions 31b include pins 33 which are engaged byoperational arms 34a of opening and closing springs 34, as shown inFIGS. 31 and 32. In other words, pins 33 are adapted to slide within,and/or be moved by, respective fork-shaped end portions of the drivingarms.

Opening and closing springs 34 are comprised, e.g., of molded syntheticresin and include the Y-shaped spring arm 34b and driving arm portions34c, in addition to the fork-shaped operational arms 34a which engagepins 33. Each of the springs is pivoted to the barrier mechanism 30 by arespective pin 35. Spring arms 34b bear against the inner wall of thefront lens group support frame 22 in order to continuously bias barrierplate portions 31a, via operational arm 34a, into positions in whichbarrier plate portions 31a are located away from the optical axis of thephotographing optical assembly, and in which the front aperture 22b ofthe frame 22 remains in an open position.

Driving arms 34c come into engagement with opposed flange portions 36aof pin 36, which is movably fitted in a radial direction within frontlens group support frame 22. As shown in FIGS. 31 and 32, pin 36 isengaged by a free end of an operational lever 38 which is pivoted tofront securing plate 13 via pin 37, through an operational aperture 39of the front group lens support frame 22. Although a pivotable actuatinglever is illustrated in the embodiments of FIGS. 31-34, any structurewhich can move pin 36 inwardly in a radial direction would besatisfactory.

Pin 36 occupies a substantially radially projecting position, under theinfluence of the spring force of spring 34, when no external force isapplied to pin 36, as is illustrated in FIG. 31. In this position, thebarrier plate portions 31a are located away from the photographingoptical axis or path, and aperture 22b remains in an open position.

A restricting projection or abutment 40 is provided on the inner wall ofcam ring 14, which is adapted to bear against the outer end of theoperational lever (or other analogous structure) 38 when the cam ringrotates in its fixed axial position into a predetermined position inorder to press pin 36 radially inwardly; this occurs when cam ring 14(pin 17) rotates within the opening and closing section 20a of zoomingcam groove 20.

With such an arrangement of the barrier mechanism, when projection 40 isnot in engagement with operational lever 38, barrier plates 31a ofbarriers 31 open photographic opening 22b. Specifically, cam ring 14causes rollers pins 17 to engage any groove section other than openingand closing section 20a of zooming cam groove 20, with barriers 31 thusbeing opened.

To the contrary, when zooming motor 5 is driven by a lock switch (notshown in the drawings) to rotate cam ring 14, so that roller 17 willmove into and engage opening and closing section 20a of zooming camgroove 20 from lens collapsing or retracting groove section 20b,projection 40 will push opening and closing pin 36, via operationallever 38, in the radial direction, and barriers 31 will rotate throughtheir engagement with spring drive arms 34c and operational arms 34a tomove the barrier plate portions 31a into the optical path of the lenssystem. As a result, the photographic opening 22b will be closed so asto protect front lens element group L1. Namely, front lens groupssupport frame 22 closes barriers 31 after the frame has been collapsedfrom the rearmost position from which a picture can be taken.

When a picture is to be taken, zooming motor 5 is reversed so as torotate cam ring 14, so that the zooming cam groove 20 will be rotatedfrom a position in which opening and closing section 20a is engaged byroller(s) 17 towards a position in which lens collapsible section 20b isso engaged. This causes barriers 31 to open and the front lens group L1is moved into a position in which a picture can be taken.

FIGS. 33 and 34 illustrate a second embodiment of a mechanism used in alens shutter type of camera in accordance with the present invention. Asshown in FIGS. 33 and 34, this barrier mechanism 30 is basicallyidentical to the embodiment illustrated in FIGS. 31 and 32.Specifically, barrier mechanism 30 in FIGS. 33 and 34 also include apair of barriers 31, 31 which are positioned in a substantiallysymmetrical fashion with respect to the photographic opening 22b offront lens group support frame 22. Barriers 31, 31 are pivoted to frame22 via pins 32 in order to open and close photographic opening 22b.However, details of construction of the barrier mechanism in thisembodiment are different from those in the first embodiment discussedabove.

Barriers 31, 31 which are illustrated in FIGS. 33 and 34 aresymmetrically disposed with respect to each other and include barrierplate portions 31a which can be projected onto the photography opticalaxis, and driving arms 31b which lie or are disposed on opposite sidesof the barrier plate portions 31a; and the barriers are pivotablyattached to the frame by pins 32.

Driving arms 31b include operational pins 133 which are engaged to, andwhich are adapted to abut or contact, a single wire spring 134 havingelastic leg portions 134a. A free end of each of the elastic legportions 134a is adapted to contact a respective pin 133 in order thatbarrier plate portions 31a will be continuously biased into an openposition in which the photographic aperture 22b is opened and thebarriers located away from the optical axis and the aperture. Thus, whenno external force is applied to barriers, they constantly maintain thephotographing aperture in an open condition.

Wire spring 134 is made from metal and has a central, U-shaped portion134b which bears against a support pin 135 provided on front lens groupsupport frame 22. Wire spring 134 has a constant spring force whichforce will not vary in accordance with changes in temperature, humidityor other environmental parameters. Accordingly, it is therefore possibleto bias barriers 31 in a direction in which a photographing aperture ismaintained in an open position by a substantially constant spring force.

Operational pins 133 are engaged by respective driving free ends 136a ofa pair of right and left driving arms 136, which are spaced from eachother and which are adapted to open barriers 31, by overcoming thebiasing force exerted by wire spring 134. The free ends 136a of each ofthe driving arms 136 bears against a respective inner side of arespective operational pin 133, which is located away from the outerside of each pin against which one elastic leg portion 134a bears.Driving arms 136 are pivoted to lens support frame 22 via pins 137.Driving arms include operational arm portions 136b located on oppositesides of the driving arms from free ends 136a, with a pin 137 providedbetween them to pivot the arm to frame 22, such that operational armportions 136b will engage flange portions 138a of pin 138, which isradially movably fitted within an opening 39 in frame 22. Pin 138includes a head (unreferenced) which is adapted to bear against the freeend of operational lever 141; the lever is pivoted to front securingplate 13 by pin 140, and the head can extend, when depressed, through anopening 39 of frame 22. The opening and closing pin 138 is normallymaintained in a position in which it projects outwardly from the innerperiphery of frame 22, and is radially movable by lever 141 into aposition in which the head of pin 138 is forced inwardly through opening39, overcoming the influence of wire spring 134. Thus when an externalforce is applied to pin 138, it moves radially inwardly against theforce of spring 134, as seen in FIG. 34.

As in the first embodiment, the cam ring 14 can be provided, along itsinner wall, with a narrowing projection 40 attached to its interiorperipheral surface which is adapted to push the operational lever 141inwardly so that it will engage operational arm portions 136b (via pinflanges 138a) when cam ring 14 rotates so that roller 17 is positionedwithin opening and closing section 20a of zooming cam groove 20. Othersuitable actuating structure could also be used.

With such an arrangement of the barrier mechanism, barriers 31 serve toopen the photographing aperture when the restriction projection 40 doesnot engage operational lever 141. Specifically, barriers 31 open whenroller 17 is located within any of the sections of the zooming camgroove other than opening and closing groove section 20a. To thecontrary, when roller 17 is moved to engage the opening and closingsection 20a, after it has been positioned within lens collapsiblesection 20b of zooming cam groove 20 (via rotation of actuating cam ring14 effected by zooming motor 5), projection 40 will push the opening andclosing pin in a radially inward direction, via operational lever 141,in order to rotate barriers 31, via driving arms 136 and operationalpins 133, so that barrier plate portions 31a will be brought into theoptical path of the lens system. In this condition, the photographicopening will be closed so as to protect the front lens element group L1.Namely, after front lens group support frame 22 is collapsed from themost extreme rearward position i.e., the extreme wide angle position, inwhich a picture can be taken, the photographic aperture will then beclosed by barriers 31.

When a picture is taken, zooming motor 5 will be reversed to rotate camring 14 from a position in which opening and closing section 20a isengaged by roller 17 to a position in which lens collapsible section 20bis so engaged, in order to open barriers 31, so that the front lenselement group L1 will move into a position in which a picture can betaken.

F. Light Interception Assembly and Mechanism

The light interception mechanisms are best illustrated in FIGS. 6 and35-38 of the present application.

In a lens shutter type of camera as described herein, the front and rearlens element groups can be independently moved along the photographingoptical axis direction in order to effect a lens zooming operation.Since a gap exists between the front lens group frame 16 and the rearlens group frame 18, and since cam ring 14, which includes through camgrooves 20 and 21 for actuating movement of lens frames 16 and 18, islocated about the outer peripheries of the lens frames, the possibilityexists that undesirable light rays would otherwise penetrate into thephotographic optical system of the camera through the gap between thefront and rear lens group frames and through the cam grooves 20 and 21.Further, since front lens group frame 22 moves through opening 201 offront cover 200 (see FIG. 6), rays of light can also enter the cameravia opening 201. The front cover 200 covers the front face of lensbarrel block 1 and supports lenses L3 and L6 of the finder as well asstrobe block 2. Opening 201 is formed along and defined by an innerflange 202 of front cover 200, so that the movable decorative frame 22,i.e., which includes the front group lens frame 16, will move throughopening 201 when the camera is in its zooming operation. An annularspace 203 having a relatively small width W is provided between innerflange 202 and front stationary plate 13. The front stationary plate issubstantially annular in configuration.

In order to prevent rays of light from penetrating into the camera, asnoted above, a light intercepting mechanism has been provided.Specifically, a light intercepting assembly 210 which comprises aplurality of sections is provided about the outer periphery of cam ring14 and is adapted to cover through or continuous cam grooves 20 and 21in order to intercept rays of light and prevent them from entering theinterior of lens barrel block 1. In the embodiment illustrated in FIG.35, intercepting assembly 210 comprises a gear ring 15, a flexible codeplate 90 which is adjacent to gear member 15 along one side of the gearmember, and a light intercepting tape 211 which extends on the oppositeside of the gear member 15. In other words, the annular gear member islocated between the flexible code plate 90 which is wrapped about lensbarrel block 1 over cam grooves 20 and 21, and the light tape 211, whichis also flexible and which is wrapped about the lens barrel block sothat it covers cam grooves 20 and 21.

Code plate 90 is provided to detect the angular position of cam ring 14in order to automatically detect a change in the focal length of thezoom lens, a change of the F number which will vary in accordance withthe changing focal length of the zoom lens, the extreme wide angleposition of the zoom lens, the extreme telephoto position of the zoomlens, the collapsed position of the zoom lens, the extreme macroposition of the zoom-lens, e.g., in order to effect a variety ofcontrols which are disclosed in detail hereinafter with respect to themechanism for detecting the position of the zoom lens and fordeciphering information relating to the position of the zoom lens.

Code plate 90 is formed from a flexible material having a lightintercepting property. Intercepting tape 211 comprises a flexiblematerial also having such a property, e.g., a dull-finish black paper.The code plate and the intercepting (paper) tape are applied to thecylindrical outer surface of cam ring 14, along opposite sides of gearmember 15, in order to cover the major portions of zooming cam grooves20 and 21. Gear 15 is preferably superimposed or overlapped over theside edges of the code plate and the intercepting tape in order toensure the interception of rays of light, as illustrated in FIG. 6.

An annular light intercepting member 220 which forms an additionalportion of the light intercepting assembly is provided in annular space203, which is defined by the space between front stationary plate 13,which rotatably supports the front portion of cam ring 14, and frontcover 200, as best seen in FIG. 6.

Annular light intercepting member 220 which is positioned within annularspace 203 comprises an elastic annular body 221, e.g., rubber, and anannular reinforcing plate 222, so that the light intercepting member 220will be have the overall configuration of a substantially flat annularring, as best illustrated in FIGS. 36 and 37. The thickness w of lightintercepting member 220 is slightly less than the width W of annularspace 203, so that the light intercepting member 220 can move over asmall distance within space 203, along the direction of thephotographing optical axis.

Elastic body 221 of light intercepting member 220 is provided, along itsinner periphery, with a light intercepting lip 223 having a small widthwhich slidably contacts the outer periphery of decorative frame 220.Reinforcing plate 222 can be secured to elastic body 221, e.g., bypartially imbedding the elastic body 221 into connecting recesses, holesor apertures 224 formed in reinforcing plate 222, which plate is made,e.g., of metal or synthetic resin. The inner lip 223 is extremelyflexible and is capable of moving in either direction axially of a lensbarrier block about which it is positioned. The lip can thus play aminor role in reducing rebound of the barrier block after it ceasesmovement in a first axial direction.

FIG. 38 illustrates a second embodiment of the annular ring illustratedin FIGS. 36 and 37, in which two spaced light intercepting lips 223(rather than merely one) are formed on the inner periphery of annularlight intercepting member 220 in order to increase the lightinterception effect of the apparatus. These lips are spaced from eachother in a parallel fashion and form a generally annular U-shaped,inwardly directed annular flange for the light intercepting member.Elastic body 221 is used to cover the outer periphery of reinforcingplate 222 in such structure.

Alternately, it would be possible to replace annular light interceptingmember 220 with a conventional O-ring structure, which would be thesimplest manner of intercepting light and preventing it from reachingundesired areas within the camera.

With such a light intercepting mechanism, undesirable light rays willnot enter the camera lens system through the circumference of the frontlens group frame 16 and/or the rear lens group frame 18, nor through thefront annular opening between the lens barrel and camera cover.

G. FPC Board Guide and Anti-Reflection Mechanism

The FPC board guide and its associated anti-reflection mechanism of theare best illustrated in FIGS. 39-43.

In a lens shutter type of camera as in the present invention, it isnecessary to provide operational signals to shutter block 23 on lensbarrel block 1 from the body of the camera. Shutter block 23 issupported by support frame 22 of front lens element group L1, andaccordingly moves together with front lens element group L1 along thedirection of the optical axis. In order to send operational signals fromthe camera body to the shutter block 23 which moves in such an opticalaxis direction, in response to outputs of the distance measuring device,i.e., the range finder, and, e.g., the exposure control device on thecamera body, a flexible printed circuit board (hereinafter referred toas an FPC board) is desirably used. The mechanism for guiding movementof the FPC board and the anti-reflection assembly which are used inconjunction with such board are described hereinbelow in detail withmore specific reference to FIGS. 39-43.

FPC board 160 (see FIGS. 39 and 40) provides operational signals toshutter block 23 from one side of the camera body. This board is madefrom a flexible synthetic resin sheet having a predetermined printedcircuit pattern thereon; in general, such FPC boards are well known.

As illustrated in FIG. 39, FPC board 160 has a connecting pattern 161 ata front end of the board to which shutter block 23 can be electricallyconnected, and a rear connecting pattern 162 to which a CPU (a centralprocessing unit which is not illustrated in the drawings) which isprovided in the camera body can be electrically connected. FPC boardguide plate 163, which guides FPC board 160, is secured to the camerabody at a base or rear portion thereof, and extends into a space betweencam ring 14 and decorative frame 22, forwardly of lens barrel block 1.Securing clips 166 are provided for attaching the FPC board 163 to theguide plate, and clamping members 167 (see FIG. 41) are provided forattaching the FPC board to the front portion of a camera body frame,e.g., which is die cast, or to the rear portion of a lens barrel frame(base 6).

A bent guide 165 is provided on the front end of FPC board 163; thisbent guide comprises a pair of front and rear guide pins 168 and 169.These guide pins are preferably stationary (although it is conceivablethat rollers could be used instead) and are adapted to maintain thecurvature of the FPC board 163 along an immovable bent portion 160a ofthe board, at which point the board extends forwardly from the camerabody and is bent in opposite directions so as to extend towards thecamera body. FPC board 160, which is bent around guide pin 168, extendsrearwardly into the gap between guide pin 169 and FPC board guide plate163, and is again freely bent forwardly by or at a movable bent portion160b.

It should be appreciated that the relative positional relationshipbetween guide pins 168 and 169, and FPC board 160, is constant,irrespective of the movement of shutter block 23 forwardly andrearwardly in an axial direction. Accordingly, guide pins 168 and 169are preferably immovable pins which are not rotatable. Alternately, itis possible to replace these pins with guide rods or shafts over whichthe FPC board will be bent in opposite directions.

As shutter block 23 moves forwardly and rearwardly, the movable bentportion 160b of the FPC board also moves forwardly and rearwardly.Although the extension of the FPC board 160 extends rearwardly from theboard guide plate 163, as shown in FIGS. 39 and 40, actually the rearextension of FPC board 160 can be bent forwardly along, and by, a bentguide 170 of guide plate 163 in order to move the board towards thefront part of the camera body.

The inner surface of FPC board 160 faces the gap between the front lensgroup frame 16 (as well as decorative frame 22) and rear group lensframe 18, and there is therefore a possibility that rays of light whichare incident upon the lens system will be reflected by FPC board 160,resulting in undesirable internal reflection. In order to prevent suchinternal reflection, an anti-reflection material or apparatus can be(and should be) provided on FPC board 160.

Several alternate solutions can be used to provide anti-reflection meanson the FPC board 160. As one solution, FPC board 160 can be formed froma dull-finish, black synthetic resin material. Alternately, the FPCboard 160 can be provided along its inner surface, i.e., on its surfacewhich is adjacent to the optical axis of the camera, with ananti-reflection sheet 171, as illustrated in FIG. 43. Such a sheet cancomprise, e.g., a dull-finish black paper or the like, and is adapted tobe placed on the FPC board 160. Preferably, the anti-reflection sheet171 is simply loosely superimposed on the FPC board without beingadhered to the board in order to provide flexibility against deformationdue to expansion and shrinkage of the material. Sheet 171 lies on theFPC board in the area between bent portions 160a and 160b of FPC board160. A third solution is to coat at least the inner surface of FPC board160 with an anti-reflective layer.

With the guide mechanism of the FPC board and with the anti-reflectionmechanism which are noted above, when the zooming motor 5 is driven torotate in order to rotate cam ring 14, front lens group frame 16 andrear lens group frame is will be moved in directions along the opticalaxis in accordance with the cam grooves 20 and 21 on cam ring 14 inorder to effect a zooming operation, and can be moved into a position inwhich the camera is in its macro setting or mode. Movement of the frontlens group frame 16 causes shutter block 23 to move in the samedirection, so that FPC board 160 will be extended in accordance withmovement of the shutter block 23. Extension of the board is madepossible by displacement of movable bent board portion 160b.Specifically, FPC board 160 is integrally connected to the CPU in thebody of the camera at rear end connecting pattern or portion 162 (seeFIG. 39) and the intermediate portion of the FPC board is guided by FPCguide plate 163. The immovable bent portion 160a of the FPC board 160 isimmovably guided by guide pins 168 and 169; and, accordingly, when thefront end connecting pattern 161 of FPC board 160 moves in accordancewith or in response to movement of shutter block 23, only the movablebent board portion 160b will be displaced forwardly and rearwardly inorder to absorb the movement of shutter block 23, as illustrated inFIGS. 40 and 42. in this fashion, FPC board 160 can be surely guidedwithin the annular space 164 located between cam ring 14 and decorativeframe 22 (FIG. 41).

Since the FPC board 160 has an anti-reflection structure as disclosedabove, internal reflections which would otherwise cause an undesirablephenomena, e.g., a flare or a ghost, will not occur.

H. Detection Mechanism for Detecting Information Relating to thePosition of the Zoom Lens

As noted previously, in a lens shutter camera formed in accordance withthe present invention, the photographic optical system is moved alongthe optical axis by the rotation of cam ring 14, so that the focallength of the photographic optical system will vary, and so that theoptical system will move from one extreme angular position of the camring into the macro setting position, and from the other extreme angularposition of the cam ring into a lens (totally) collapsed position. Insuch a lens shutter type of camera, which includes a zoom lens, it isnecessary, e.g., to detect the focal length of the photographic opticalsystem, the macro setting position, and the two extreme positions of thecam ring in order to indicate the focal length, to control the exposurewhich varies in accordance with the F number, and to control thedirection of rotation of the motor which drives the cam ring.

In the present invention, the above information, i.e., relating to thefocal length and the two extreme positions of th zoom lens, can easilybe detected by code signals on the single flexible code plate 90 whichis provided on cam ring 14. Specifically, code plate 90, as illustratedin FIG. 44, is provided on cam ring 14 (which is shown in FIG. 1) and isbrought into sliding contact with a brush 92 (FIG. 44) which is securedat its base end to a stationary frame 91 positioned on the outside ofcam ring 14. This is well illustrated in FIG. 1.

FIG. 44 illustrates the developed code plate 90, in a flattenedcondition, in which the upper half of the drawing illustrates the camprofiles of zooming cam groove 20 and 21 of cam ring 14, and cam grooves55, 56 and 57 of cam plate 53, respectively. Brush 92 includes a commonterminal C and independent (bristles) terminals T0, T1, T2, and T3. Wheneach of terminals T0-T3 is electrically connected to the conductivelands 93 of code plate 90, a signal "0" is issued, and when each of theterminals T0-T3 are not electrically connected to conductive lands 93,a. signal "1" is issued. The angular position of cam ring 14 can bedetected by the combination of signals "0" and "1". A plurality of dummyterminals 94 are formed in conductive lands 93. The purpose of the dummyterminals, which are formed from the same material as conductive lands93, is that the flexible code plate bent about the cam ring, and inorder to improve the physical strength of the plate and still provide anarea without electrical contact the dummy terminals were so positionedto increase flexibility while preserving strength. Additionally, thesedummy terminals provide (non-conductive) lands upon which the terminalsT0-T3 of the brush can ride as the cam ring is rotated.

The four bit information received from terminals T0-T3 are provided aszoom code data ZP0, ZP1, ZP2, and ZP3, respectively, of a zoom codeencoder, as is clearly illustrated in FIG. 45. This figure comprises atable of combinations of signals "0" and "1", in which the angularposition, i.e., POS, of cam ring 14 is divided into 13 steps between "0"and "9", and "A", "B", and "C", respectively, which are hexadecimalnumbers. The number "0" designates a locked position, and the "C"position designates a position in which the camera is in its macro mode.Between the locked position and the macro position, there are nine focallength positions f0-f7'. The locked position and the macro positioncorrespond to the two extreme angular positions of the cam ring 14.Zooming motor 5 is controlled so that the cam ring 14 will not rotatebeyond the two extreme positions. These angular or rotational positionsare shown on the code plate in FIG. 44.

Rotation of cam ring 14 is controlled by the mode changing switch 101and the zoom switch 102, which are illustrated in FIGS. 47-50, inaccordance with positional information of cam ring 14 as determined bycode plate 90.

The arrangement of mode changing switch 101 and zoom switch 102 on thecamera body is illustrated in FIGS. 46-48. A release button 99 isprovided on the upper surface of the camera which can be pushed by onestep to turn a photometry switch into an ON position, and which can bepushed by two steps to turn a release switch into an ON position(neither of these two switches are shown in the drawings, however). Modechanging switch 101 is a transfer switch which can occupy 3 positions,i.e., a lock position (LOCK), a zooming position (i.e., ZOOM), and amacro position, i.e. (MACRO). As illustrated in FIGS. 49-50, when macrobutton 101a is not depressed, switch lever 101b can move between theLOCK and ZOOM positions. When macro button 101a is depressed, however,and when switch lever 101b slides onto the upper surface of macro button101a, the macro mode of the camera will be set. FIGS. 49 and 50 arecross-sections of the macro and zoom-lock switches, respectively. Whenin the LOCK position, neither the releasing operation nor the zoomingoperation of the zoom lens can be effected. In the ZOOM position,however, the release operation and the zooming operation can be carriedout. In the MACRO position, the releasing operation can be performed butthe zooming operation cannot be effected.

FIG. 51 illustrates an alternate arrangement of the zoom switch, inwhich the zoom lens is moved towards a telephoto position when atelephoto button T is pushed and towards a wide angle position when awide angle button W is pushed.

Zoom switch 102 occupies a neutral position, i.e., it is placed into anOFF position, when no external force is applied to the switch; and itcan be manually moved into a wide angle position, i.e., a WIDE position,and into a telephoto position, i.e., a TELE position, which positionsare located on opposite sides of the neutral "OFF" position. Zoomingmotor 5 can be rotated in both forward and reverse directions byswitching the position of zoom switch 102 between the WIDE and TELEpositions.

Mode changing switch 101 and zoom switch 102 actuate the camera of thepresent invention as detailed hereinafter. In actual use, positionalinformation relating to the position of cam ring 14 which is indicatedby code plate 90 will be used.

1. For the LOCK position of the mode changing switch 101, zooming motor5 is reversed to rotate cam ring 14. When the angular position POS ofcam ring 14 becomes "0" (see FIGS. 44 and 45) as detected by code plate90 and brush 92, zooming motor 5 will stop rotating.

2. For the MACRO position of the mode changing switch 101, zooming motor5 rotates in the forward direction and stops rotating when POS reachesthe "C" position.

3. For the ZOOM position of the mode changing switch 101, zooming motor5 reverses when zoom switch 102 is in the WIDE position, and rotates inthe forward direction when the zooming switch is in the TELE position.Zooming motor 5 will stop rotating when POS reaches the "A" position,when the zoom switch is in the TELE position. When the zoom switch is inits WIDE position, zooming motor 5 will continue reversing for apredetermined short span of time after POS reaches the "1" position.After this time, zooming motor 5 will begin rotating in a forwarddirection and will stop rotating when POS becomes 2.

When zoom switch 102 is turned to the OFF, i.e., neutral, position,during rotation of zooming motor 5, the zooming motor will immediatelystop rotating when the zoom switch is in the TELE position, and willstop after it rotates in the forward direction for a predetermined shortperiod of time when it is in the WIDE position, respectively.

Details of several of the positions will now be described.

POS 1: Since the code signals change at the LOCK position and at theextreme WIDE position, these extreme positions are detected. Moreprecisely speaking, the LOCK position is not "POS 0", but is instead apoint which is located between POS 0 and POS 1. However, when the camerais in the LOCK position, the brush is in POS 0, in a location very closeto POS 1. Similarly, the WIDE extreme position is a point between POS 1and POS 2. However, when the camera is in the extreme WIDE position,(which is not a wide zone), brush 92 is in POS 2, which is very close toPOS 1. Accordingly, POS 1 denotes a range in which the cam ring 14 movesfrom the extreme WIDE position to the LOCK position, and vice versa.

POS f7': This zone is provided for absorbing the backlash of cam ring 14(is., backlash from movement of the lens system). Specifically, asillustrated in FIG. 45, during rotation of the cam ring from POS 0towards POS C, the cam ring will stop immediately when a stop signal isgiven, i.e., when the zoom switch is turned to an off position. To thecontrary, rotation of the cam ring from POS C towards POS 0 causes thecam ring 14 to reverse slightly after it overruns its desired positionby a predetermined displacement, and then stops the cam ring at a firstchanging POS point. POS f7' is the extreme TELE position, and,accordingly, when cam ring is in its extreme TELE position (with theTELE zone being a zone in which the cam ring operates at the TELEexposure), the brush will be located at position POS A, which is veryclose to POS 9. The focal length information or the F number informationare fed to the shutter by the code plate and the brush. Accordingly, thesame focal length information is fed at the TELE zone and the TELEextreme positions. This is the reason that POS 9 is represented by f7and POS A is represented by f7' in order to distinguish it from f7. Thezone f7' is quite small, and accordingly the zone f7' can essentially beconsidered identical to the extreme TELE position.

POS B: In a fashion similar to POS 1, this zone is provided todistinguish the extreme MACRO and TELE positions. Unlike POS 1, in whichthe WIDE extreme position is a changing point between POS 1 and the WIDEextreme position, and POS B is an extreme TELE position representingchanging points between POS 9 and POS A, respectively.

POS 2≃POS A: These are intermediate focal length positions whichcomprise a plurality, e.g., 9 in the illustrated embodiment, steps.

The CPU then checks the code information and the setting positions forthe various switches when they are turned into their ON positions. Ifthe mode changing switch is in a zoom position, no zooming will benecessary when the cam ring is in any position between and including POS2 and POS A. If, however, the mode changing switch is in a positionother than the zoom position, i.e., in either the LOCK position, anintermediate position between LOCK and WIDE, an intermediate positionbetween TELE and MACRO, or the MACRO position, zooming operation of thelens will be immediately effected. This is also true when the switch isbrought into the zoom position during rotation of the zooming motor inthe forward direction and when the switch is brought into. the zoomposition during reverse rotation of the zooming motor. Specifically,when in the zoom position, whether the zoom code is within the rangebetween and including POS 2 to POS A (within which range zooming iseffected) will be checked by the CPU. If the zoom code is out of therange, no picture can be taken, and, accordingly, the cam ring will bemoved into the zooming position. In other words, POS 1 and POS B areareas in which the cam ring is prohibited from stopping and in which apicture cannot be taken.

Of course, it is clear that the present invention is not limited to theembodiments described above, nor those illustrated in the drawings, andthe invention can be modified without departing from the spirit andscope of the claimed invention.

We claim:
 1. A zoom lens shutter camera having a finder optical assemblyand an image forming optical assembly with different optical axes, saidimage forming optical assembly including a zoom lens, said cameraincluding a system for moving said finder optical assembly inassociation with zooming movement of said zoom lens in order to vary thefield of view through said finder optical assembly in accordance withchanges in position of said zoom lens, said zoom lens comprising a firstlens group and a second lens group, said camera further comprising ashutter block mounted around at least one of said first lens group andsaid second lens group, said shutter block being drivably connected to amovable driving ring, wherein movement of said driving ring moves saidshutter block axially along said image forming optical axis and effectszooming movement of said zoom lens.
 2. The zoom lens shutter camera inaccordance with claim 1, wherein said driving ring is rotatable, andwherein rotation of said driving ring moves said shutter block and saidfirst lens group along said image forming optical axis during a zoomingoperation.
 3. The zoom lens shutter camera in accordance with claim 2,wherein said driving ring is stationary along said image forming opticalaxis.
 4. The zoom lens shutter camera in accordance with claim 1,wherein said driving ring comprises a cam ring.
 5. The zoom lens shuttercamera in accordance with claim 1, further comprising a zooming motorfor driving said first lens group and said second lens group during azooming operation of said zoom lens.
 6. The zoom lens shutter camera inaccordance with claim 1, further comprising a motor for driving saidfirst lens group relative to said shutter block during a focusingoperation.
 7. The zoom lens shutter camera in accordance with claim 1,said driving ring comprising a first cam groove for guiding movement ofsaid first lens group and a second cam groove for guiding movement ofsaid second lens group.
 8. The zoom lens shutter camera in accordancewith claim 1, further comprising a zooming motor for driving said firstlens group and said second lens group, said driving ring comprising agear segment for transmitting a drive force of said zooming motor tosaid first lens group and to said second lens group.
 9. The zoom lensshutter camera in accordance with claim 1, further comprising a codeplate and a brush unit positioned to engage said code plate, one of saidcode plate and said brush unit being secured to said driving ring. 10.The zoom lens shutter camera in accordance with claim 1, wherein saiddriving ring is rotatable, said camera further comprising at least oneaxially extending guide member, said shutter block being movablypositioned on said at least one axially extending guide member toprevent rotation of said shutter block when said driving ring rotates,wherein said shutter block moves axially in response to rotation of saiddrive ring.
 11. The zoom lens shutter camera in accordance with claim10, wherein said shutter block includes a frame with an aperture, andwherein said at least one guide rod extends through said aperture. 12.The zoom lens shutter camera in accordance with claim 1, said drivingring including at least two grooves, said shutter block being attachedto a frame having a pin engaged in a first one of said grooves and saidfirst lens group being attached to a frame having a pin engaged in asecond one of said grooves.
 13. The zoom lens shutter camera inaccordance with claim 1, wherein a frame member is attached to saidshutter block, said frame member having a pin which is engaged by agroove provided in said driving ring.
 14. The zoom lens shutter camerain accordance with claim 13, said frame member including an aperturewhich is slidably positioned on a guide rod extending generally parallelto said image forming optical axis.
 15. The zoom lens shutter camera inaccordance with claim 1, said finder optical assembly including at leastone stationary lens and at least one lens movable in a directionparallel to an optical axis of said finder optical assembly.
 16. Thezoom lens shutter camera in accordance with claim 15, further includingmeans for transmitting motion of said driving ring to said at least onemovable lens of said finder optical assembly.
 17. The zoom lens shuttercamera in accordance with claim 16, said at least one movable lens ofsaid finder optical assembly including a lens frame, said lens framehaving a pin cooperating with a camming structure for moving said atleast one movable lens of said finder optical assembly in accordancewith movement of said driving ring.
 18. The zoom lens shutter camera inaccordance with claim 1, said driving ring further comprising a gearpositioned about an outer surface of said driving ring and beingdrivingly rotated by a motor, said finder optical assembly also beingdriven by said motor.
 19. The zoom lens shutter camera in accordancewith claim 1, further comprising a code plate which is slidably engagedby a plurality of conductive brushes, wherein free ends of said brushesselectively contact regions of said code plate in accordance withmovement of said zoom lens.
 20. The zoom lens shutter camera inaccordance with claim 1, further comprising a flexible printed circuitboard for conducting operational signals from a camera body to saidaxially movable shutter block.